Conference Coverage

SAN DIEGO – The presence of five key proteins in the blood was strongly associated with the development of metabolic dysfunction-associated steatotic liver disease (MASLD) as much as 16 years before symptoms appeared, new research showed.

“This represents the first high-performance, ultra-early (16 years) predictive model for MASLD,” said first author Shiyi Yu, MD, resident physician in the department of gastroenterology, Guangdong Provincial People’s Hospital in China.

“The findings could be a game-changer for how we screen for and intervene in liver disease,” Yu said at a press briefing for Digestive Disease Week® (DDW) 2025.

“Instead of waiting for symptoms or irreversible damage, we can [identify] high-risk individuals early and take steps to prevent MASLD from developing, which is particularly important because MASLD often progresses silently until advanced stages,” she added.

MASLD is the most common liver disorder in the world and carries a high risk of morbidity and mortality, with a mortality rate that is doubled compared with those without MASLD.

To identify any long-term predictive markers that could be used in simple predictive models, Yu and colleagues evaluated data on 52,952 participants enrolled in the UK Biobank between 2006 and 2010 who did not have MASLD at baseline and were followed up for up to 16.6 years.

Overall, 782 participants were diagnosed with MASLD over the course of the study.

A total of 2,737 blood proteins were analyzed, and among them, the five that emerged as being robust predictive biomarkers for development of MASLD within 5 years included CDHR2 (area under the curve [AUC] = 0.825), FUOM (AUC = 0.815), KRT18 (AUC = 0.810), ACY1 (AUC = 0.803), and GGT1 (AUC = 0.797). 

Deviations of the proteins in plasma concentrations were observed up to 16 years prior to MASLD onset, with higher levels of the proteins at baseline associated with up to a nearly 10-times higher risk of MASLD (hazard ratios, 7.05-9.81). 

A combination of the five proteins was predictive of incident MASLD at all time frames, including at 5-years (AUC = 0.857), 10-years (AUC = 0.775), and at all time points (AUC = 0.758).

The combined proteins gained even stronger predictive performance when added to key clinical biomarkers such as BMI and daily exercise, with an accuracy of 90.4% at 5 years and 82.2% at 16 years, “surpassing all existing short-term prediction models,” Yu reported.

Similar results were observed with the predictive model in a separate, smaller cohort of 100 participants in China, “further supporting the robustness of the model and showing it can be effective across diverse populations,” she noted in the press briefing.

 

Potential for Interventions ‘Years Before’ Damage Begins

Yu underscored the potential benefits of informing patients of their risk of MASLD.

“Too often, people do not find out they are at risk for liver disease before they are diagnosed and coping with symptoms,” she said.

A protein-based risk score could “profoundly transform early intervention strategies, triggering personalized lifestyle interventions for high-risk individuals” she said. 

With obesity, type 2 diabetes, and high cholesterol levels among key risk factors for MASLD, such personalized interventions could include “counseling on diet, physical activity, and other factors years before liver damage begins, potentially averting disease progression altogether,” Yu noted.

Instead of waiting for abnormal liver function tests or imaging findings, patients could receive more frequent monitoring with annual elastography or ultrasound, for example, she explained.

In addition, “knowing one’s individualized protein-based risk may be more effective than abstract measures such as BMI or liver enzymes in motivating patients, facilitating better patient engagement and adherence,” Yu said.While noting that more work is needed to understand the biology behind the biomarkers, Yu underscored that “this is a big step toward personalized prevention.”

“By finding at-risk patients early, we hope to help stop MASLD before it starts,” she concluded.

 

Predictive Performance Impressive

Commenting on the study at the press briefing, Loren A. Laine, MD, AGAF, professor of medicine and chief of the Section of Digestive Diseases at the Yale School of Medicine, New Haven, Conn., and council chair of DDW 2025, noted that — as far as AUCs go — even a ranking in the 80% range is considered good. “So, for this to have an accuracy up to the 90s indicates a really excellent [predictive] performance,” he explained.

Laine agreed that the study findings have “the potential value to identify individuals at increased risk,” allowing for early monitoring and interventions. 

The interventions “could be either general, such as things like diet and lifestyle, or more specific,” based on the function of these proteins, he added.

Rotonya Carr, MD, the division head of gastroenterology at the University of Washington, Seattle, further highlighted the pressing need for better predictive tools in MASLD.

“The predictions are that if we don’t do anything, as many as 122 million people will be impacted by MASLD” in the US by 2050, she told GI & Hepatology News. 

“So, I am very excited about this work because we really don’t have anything right now that predicts who is going to get MASLD,” she said. “We are going to need tools like this, where people have information about their future health in order to make decisions.”

MASLD is known to be a significant risk factor for cardiovascular disease (CVD), and Carr speculated that the findings could lead to the types of predictive tools already available for CVD.

“I see this as being akin to what cardiology has had for quite some time, where they have cardiovascular risk disease calculators in which patients or their physicians can enter data and then estimate their risk of developing cardiovascular disease over, for instance, 10 years,” she said.

Laine’s disclosures include consulting and/or relationships with Medtronic, Phathom Pharmaceuticals, Biohaven, Celgene, Intercept, Merck, and Pfizer. Carr’s disclosures include relationships with Intercept and Novo Nordisk and research funding from Merck.

A version of this article appeared on Medscape.com.

SAN DIEGO – The presence of five key proteins in the blood was strongly associated with the development of metabolic dysfunction-associated steatotic liver disease (MASLD) as much as 16 years before symptoms appeared, new research showed.

“This represents the first high-performance, ultra-early (16 years) predictive model for MASLD,” said first author Shiyi Yu, MD, resident physician in the department of gastroenterology, Guangdong Provincial People’s Hospital in China.

“The findings could be a game-changer for how we screen for and intervene in liver disease,” Yu said at a press briefing for Digestive Disease Week® (DDW) 2025.

“Instead of waiting for symptoms or irreversible damage, we can [identify] high-risk individuals early and take steps to prevent MASLD from developing, which is particularly important because MASLD often progresses silently until advanced stages,” she added.

MASLD is the most common liver disorder in the world and carries a high risk of morbidity and mortality, with a mortality rate that is doubled compared with those without MASLD.

To identify any long-term predictive markers that could be used in simple predictive models, Yu and colleagues evaluated data on 52,952 participants enrolled in the UK Biobank between 2006 and 2010 who did not have MASLD at baseline and were followed up for up to 16.6 years.

Overall, 782 participants were diagnosed with MASLD over the course of the study.

A total of 2,737 blood proteins were analyzed, and among them, the five that emerged as being robust predictive biomarkers for development of MASLD within 5 years included CDHR2 (area under the curve [AUC] = 0.825), FUOM (AUC = 0.815), KRT18 (AUC = 0.810), ACY1 (AUC = 0.803), and GGT1 (AUC = 0.797). 

Deviations of the proteins in plasma concentrations were observed up to 16 years prior to MASLD onset, with higher levels of the proteins at baseline associated with up to a nearly 10-times higher risk of MASLD (hazard ratios, 7.05-9.81). 

A combination of the five proteins was predictive of incident MASLD at all time frames, including at 5-years (AUC = 0.857), 10-years (AUC = 0.775), and at all time points (AUC = 0.758).

The combined proteins gained even stronger predictive performance when added to key clinical biomarkers such as BMI and daily exercise, with an accuracy of 90.4% at 5 years and 82.2% at 16 years, “surpassing all existing short-term prediction models,” Yu reported.

Similar results were observed with the predictive model in a separate, smaller cohort of 100 participants in China, “further supporting the robustness of the model and showing it can be effective across diverse populations,” she noted in the press briefing.

 

Potential for Interventions ‘Years Before’ Damage Begins

Yu underscored the potential benefits of informing patients of their risk of MASLD.

“Too often, people do not find out they are at risk for liver disease before they are diagnosed and coping with symptoms,” she said.

A protein-based risk score could “profoundly transform early intervention strategies, triggering personalized lifestyle interventions for high-risk individuals” she said. 

With obesity, type 2 diabetes, and high cholesterol levels among key risk factors for MASLD, such personalized interventions could include “counseling on diet, physical activity, and other factors years before liver damage begins, potentially averting disease progression altogether,” Yu noted.

Instead of waiting for abnormal liver function tests or imaging findings, patients could receive more frequent monitoring with annual elastography or ultrasound, for example, she explained.

In addition, “knowing one’s individualized protein-based risk may be more effective than abstract measures such as BMI or liver enzymes in motivating patients, facilitating better patient engagement and adherence,” Yu said.While noting that more work is needed to understand the biology behind the biomarkers, Yu underscored that “this is a big step toward personalized prevention.”

“By finding at-risk patients early, we hope to help stop MASLD before it starts,” she concluded.

 

Predictive Performance Impressive

Commenting on the study at the press briefing, Loren A. Laine, MD, AGAF, professor of medicine and chief of the Section of Digestive Diseases at the Yale School of Medicine, New Haven, Conn., and council chair of DDW 2025, noted that — as far as AUCs go — even a ranking in the 80% range is considered good. “So, for this to have an accuracy up to the 90s indicates a really excellent [predictive] performance,” he explained.

Laine agreed that the study findings have “the potential value to identify individuals at increased risk,” allowing for early monitoring and interventions. 

The interventions “could be either general, such as things like diet and lifestyle, or more specific,” based on the function of these proteins, he added.

Rotonya Carr, MD, the division head of gastroenterology at the University of Washington, Seattle, further highlighted the pressing need for better predictive tools in MASLD.

“The predictions are that if we don’t do anything, as many as 122 million people will be impacted by MASLD” in the US by 2050, she told GI & Hepatology News. 

“So, I am very excited about this work because we really don’t have anything right now that predicts who is going to get MASLD,” she said. “We are going to need tools like this, where people have information about their future health in order to make decisions.”

MASLD is known to be a significant risk factor for cardiovascular disease (CVD), and Carr speculated that the findings could lead to the types of predictive tools already available for CVD.

“I see this as being akin to what cardiology has had for quite some time, where they have cardiovascular risk disease calculators in which patients or their physicians can enter data and then estimate their risk of developing cardiovascular disease over, for instance, 10 years,” she said.

Laine’s disclosures include consulting and/or relationships with Medtronic, Phathom Pharmaceuticals, Biohaven, Celgene, Intercept, Merck, and Pfizer. Carr’s disclosures include relationships with Intercept and Novo Nordisk and research funding from Merck.

A version of this article appeared on Medscape.com.

SAN DIEGO – The presence of five key proteins in the blood was strongly associated with the development of metabolic dysfunction-associated steatotic liver disease (MASLD) as much as 16 years before symptoms appeared, new research showed.

“This represents the first high-performance, ultra-early (16 years) predictive model for MASLD,” said first author Shiyi Yu, MD, resident physician in the department of gastroenterology, Guangdong Provincial People’s Hospital in China.

“The findings could be a game-changer for how we screen for and intervene in liver disease,” Yu said at a press briefing for Digestive Disease Week® (DDW) 2025.

“Instead of waiting for symptoms or irreversible damage, we can [identify] high-risk individuals early and take steps to prevent MASLD from developing, which is particularly important because MASLD often progresses silently until advanced stages,” she added.

MASLD is the most common liver disorder in the world and carries a high risk of morbidity and mortality, with a mortality rate that is doubled compared with those without MASLD.

To identify any long-term predictive markers that could be used in simple predictive models, Yu and colleagues evaluated data on 52,952 participants enrolled in the UK Biobank between 2006 and 2010 who did not have MASLD at baseline and were followed up for up to 16.6 years.

Overall, 782 participants were diagnosed with MASLD over the course of the study.

A total of 2,737 blood proteins were analyzed, and among them, the five that emerged as being robust predictive biomarkers for development of MASLD within 5 years included CDHR2 (area under the curve [AUC] = 0.825), FUOM (AUC = 0.815), KRT18 (AUC = 0.810), ACY1 (AUC = 0.803), and GGT1 (AUC = 0.797). 

Deviations of the proteins in plasma concentrations were observed up to 16 years prior to MASLD onset, with higher levels of the proteins at baseline associated with up to a nearly 10-times higher risk of MASLD (hazard ratios, 7.05-9.81). 

A combination of the five proteins was predictive of incident MASLD at all time frames, including at 5-years (AUC = 0.857), 10-years (AUC = 0.775), and at all time points (AUC = 0.758).

The combined proteins gained even stronger predictive performance when added to key clinical biomarkers such as BMI and daily exercise, with an accuracy of 90.4% at 5 years and 82.2% at 16 years, “surpassing all existing short-term prediction models,” Yu reported.

Similar results were observed with the predictive model in a separate, smaller cohort of 100 participants in China, “further supporting the robustness of the model and showing it can be effective across diverse populations,” she noted in the press briefing.

 

Potential for Interventions ‘Years Before’ Damage Begins

Yu underscored the potential benefits of informing patients of their risk of MASLD.

“Too often, people do not find out they are at risk for liver disease before they are diagnosed and coping with symptoms,” she said.

A protein-based risk score could “profoundly transform early intervention strategies, triggering personalized lifestyle interventions for high-risk individuals” she said. 

With obesity, type 2 diabetes, and high cholesterol levels among key risk factors for MASLD, such personalized interventions could include “counseling on diet, physical activity, and other factors years before liver damage begins, potentially averting disease progression altogether,” Yu noted.

Instead of waiting for abnormal liver function tests or imaging findings, patients could receive more frequent monitoring with annual elastography or ultrasound, for example, she explained.

In addition, “knowing one’s individualized protein-based risk may be more effective than abstract measures such as BMI or liver enzymes in motivating patients, facilitating better patient engagement and adherence,” Yu said.While noting that more work is needed to understand the biology behind the biomarkers, Yu underscored that “this is a big step toward personalized prevention.”

“By finding at-risk patients early, we hope to help stop MASLD before it starts,” she concluded.

 

Predictive Performance Impressive

Commenting on the study at the press briefing, Loren A. Laine, MD, AGAF, professor of medicine and chief of the Section of Digestive Diseases at the Yale School of Medicine, New Haven, Conn., and council chair of DDW 2025, noted that — as far as AUCs go — even a ranking in the 80% range is considered good. “So, for this to have an accuracy up to the 90s indicates a really excellent [predictive] performance,” he explained.

Laine agreed that the study findings have “the potential value to identify individuals at increased risk,” allowing for early monitoring and interventions. 

The interventions “could be either general, such as things like diet and lifestyle, or more specific,” based on the function of these proteins, he added.

Rotonya Carr, MD, the division head of gastroenterology at the University of Washington, Seattle, further highlighted the pressing need for better predictive tools in MASLD.

“The predictions are that if we don’t do anything, as many as 122 million people will be impacted by MASLD” in the US by 2050, she told GI & Hepatology News. 

“So, I am very excited about this work because we really don’t have anything right now that predicts who is going to get MASLD,” she said. “We are going to need tools like this, where people have information about their future health in order to make decisions.”

MASLD is known to be a significant risk factor for cardiovascular disease (CVD), and Carr speculated that the findings could lead to the types of predictive tools already available for CVD.

“I see this as being akin to what cardiology has had for quite some time, where they have cardiovascular risk disease calculators in which patients or their physicians can enter data and then estimate their risk of developing cardiovascular disease over, for instance, 10 years,” she said.

Laine’s disclosures include consulting and/or relationships with Medtronic, Phathom Pharmaceuticals, Biohaven, Celgene, Intercept, Merck, and Pfizer. Carr’s disclosures include relationships with Intercept and Novo Nordisk and research funding from Merck.

A version of this article appeared on Medscape.com.

SAN DIEGO – Patients carrying at least one of the four key genes show a significantly increased risk for disease recurrence and mortality in gastric cancer, according to new research that potentially paves the way for precision oncology and improved targeting of therapies.

“About a third of patients with gastric cancer in our study had somatic mutations or variants of uncertain significance in [one of] four key genes,” lead author Ulysses Ribeiro, MD, PhD, a professor of digestive system surgery at the University of São Paulo School of Medicine in São Paulo, Brazil, said in a press briefing for the study, presented at Digestive Disease Week® (DDW) 2025.

“These patients were more likely to have their cancer come back or to die from the disease, even after surgery and the best chemotherapy and immunotherapy regimens,” said Ribeiro. While treatment strategies in gastric cancer have improved in recent years, resistance to multiple drugs continues, and the 5-year overall survival rate remains low — about 36% — underscoring the critical need for targeted therapies.

In an effort to identify genetic alterations that could have prognostic value, Ribeiro and his colleagues used next-generation DNA sequencing to analyze 21 genes in the tumor samples of 87 patients with gastric cancer who had undergone curative surgery and chemotherapy at the Sao Paulo Cancer Institute, São Paulo, Brazil.

Using Cox regression analysis, they found pathogenic variants or variants of uncertain significance in the following four genes: BRCA2, CDH1, RHOA, and TP53. “We found that 33% of patients carried at least one of these four genes,” Ribeiro told GI & Hepatology News.

Individually, each of the four genes with pathogenic variants or variants of uncertain significance had significantly or near-significantly higher risks in a survival analysis vs wild-type or benign variants, including BRCA2 (hazard ratio [HR], 4.33; P = .030); CDH1 (HR, 7.54; P = .004); RHOA (HR, 29.24; P < .001); and TP53 (HR, 2.82; P = .07).

A further multivariate analysis adjusting for key confounders showed that, when combined, carriers of the genes had lower disease-free survival (P = .005) and worse overall survival (P = .009) than those with none of the mutations.

“Individually, all four genes were related to prognosis in our gastric cancer patients, and when combined, the genes had even a higher difference in prognosis, varying from 2 to 28 times higher,” Ribeiro said.

Overall, factors such as having a more advanced tumor, node, metastasis stage, pathological stage, and the presence of a pathogenic mutation or a variant of uncertain significance in the four genes in the model were independently associated with worse disease-free survival.

 

Familiar Genes

Some of these genes are highly familiar. BRCA2 is well-known for its role in increasing the risk for breast and ovarian cancers, and CDH1 is known to be associated with hereditary diffuse gastric cancer, which is the most common hereditary cancer syndrome linked to gastric cancer.

TP53, also known as the “guardian of the genome,” is the most commonly altered gene in human cancers, while RHOA is known to be involved in encoding the GTPase protein RhoA, which is key in the regulation of cell shape, motility, and other essential cellular processes.

“This is the first time that these four genes have been shown to strongly relate to these gastric cancer outcomes,” said Ribeiro. This suggests that there’s more than one pathway by which stomach cancer forms and that some stomach cancers are much more aggressive than others.

He noted that “patients without these high-risk mutations” could be given “less aggressive treatment, in some cases sparing them from unnecessary side effects.”

Speaking during the press briefing, Loren A. Laine, MD, AGAF, who is a professor of medicine and chief of the Section of Digestive Diseases at the Yale School of Medicine in New Haven, Connecticut, and council chair of DDW 2025, agreed that “certainly, if these genetic factors, along with other factors, predict risk, this also has implications in practice with respect to the level of monitoring during the follow-up and determining the need for therapy.”

In addition, “it will be interesting to see how much this adds to other known risk factors, such as pathologic stage,” said Laine.

A strength of this study, “which I think is unique, is that it looks at a Western population,” whereas data on gastric as well as esophageal cancer is heavily biased to Eastern regions like China and East Asia, where the rates are much higher than in the West, Alia Qureshi, MD, an associate professor of esophageal and gastric cancer surgery at Oregon Health & Science University in Portland, Oregon, told GI & Hepatology News.

While noting the limitation of the relatively small sample size, Qureshi said the study is nevertheless “exciting and moving the direction we want to go, specifically towards precision medicine [and] precision oncology.”

The study “builds on existing understanding, especially with regard to TP53 and CDH1, and it points to the opportunity to use this data in a way to direct patient care or possibly therapeutic intervention,” she said.

Laine’s disclosures include consulting and/or relationships with Medtronic, Phathom Pharmaceuticals, Biohaven, Celgene, Intercept Pharmaceuticals, Merck, and Pfizer. Qureshi had no disclosures to report.

A version of this article appeared on Medscape.com.

SAN DIEGO – Patients carrying at least one of the four key genes show a significantly increased risk for disease recurrence and mortality in gastric cancer, according to new research that potentially paves the way for precision oncology and improved targeting of therapies.

“About a third of patients with gastric cancer in our study had somatic mutations or variants of uncertain significance in [one of] four key genes,” lead author Ulysses Ribeiro, MD, PhD, a professor of digestive system surgery at the University of São Paulo School of Medicine in São Paulo, Brazil, said in a press briefing for the study, presented at Digestive Disease Week® (DDW) 2025.

“These patients were more likely to have their cancer come back or to die from the disease, even after surgery and the best chemotherapy and immunotherapy regimens,” said Ribeiro. While treatment strategies in gastric cancer have improved in recent years, resistance to multiple drugs continues, and the 5-year overall survival rate remains low — about 36% — underscoring the critical need for targeted therapies.

In an effort to identify genetic alterations that could have prognostic value, Ribeiro and his colleagues used next-generation DNA sequencing to analyze 21 genes in the tumor samples of 87 patients with gastric cancer who had undergone curative surgery and chemotherapy at the Sao Paulo Cancer Institute, São Paulo, Brazil.

Using Cox regression analysis, they found pathogenic variants or variants of uncertain significance in the following four genes: BRCA2, CDH1, RHOA, and TP53. “We found that 33% of patients carried at least one of these four genes,” Ribeiro told GI & Hepatology News.

Individually, each of the four genes with pathogenic variants or variants of uncertain significance had significantly or near-significantly higher risks in a survival analysis vs wild-type or benign variants, including BRCA2 (hazard ratio [HR], 4.33; P = .030); CDH1 (HR, 7.54; P = .004); RHOA (HR, 29.24; P < .001); and TP53 (HR, 2.82; P = .07).

A further multivariate analysis adjusting for key confounders showed that, when combined, carriers of the genes had lower disease-free survival (P = .005) and worse overall survival (P = .009) than those with none of the mutations.

“Individually, all four genes were related to prognosis in our gastric cancer patients, and when combined, the genes had even a higher difference in prognosis, varying from 2 to 28 times higher,” Ribeiro said.

Overall, factors such as having a more advanced tumor, node, metastasis stage, pathological stage, and the presence of a pathogenic mutation or a variant of uncertain significance in the four genes in the model were independently associated with worse disease-free survival.

 

Familiar Genes

Some of these genes are highly familiar. BRCA2 is well-known for its role in increasing the risk for breast and ovarian cancers, and CDH1 is known to be associated with hereditary diffuse gastric cancer, which is the most common hereditary cancer syndrome linked to gastric cancer.

TP53, also known as the “guardian of the genome,” is the most commonly altered gene in human cancers, while RHOA is known to be involved in encoding the GTPase protein RhoA, which is key in the regulation of cell shape, motility, and other essential cellular processes.

“This is the first time that these four genes have been shown to strongly relate to these gastric cancer outcomes,” said Ribeiro. This suggests that there’s more than one pathway by which stomach cancer forms and that some stomach cancers are much more aggressive than others.

He noted that “patients without these high-risk mutations” could be given “less aggressive treatment, in some cases sparing them from unnecessary side effects.”

Speaking during the press briefing, Loren A. Laine, MD, AGAF, who is a professor of medicine and chief of the Section of Digestive Diseases at the Yale School of Medicine in New Haven, Connecticut, and council chair of DDW 2025, agreed that “certainly, if these genetic factors, along with other factors, predict risk, this also has implications in practice with respect to the level of monitoring during the follow-up and determining the need for therapy.”

In addition, “it will be interesting to see how much this adds to other known risk factors, such as pathologic stage,” said Laine.

A strength of this study, “which I think is unique, is that it looks at a Western population,” whereas data on gastric as well as esophageal cancer is heavily biased to Eastern regions like China and East Asia, where the rates are much higher than in the West, Alia Qureshi, MD, an associate professor of esophageal and gastric cancer surgery at Oregon Health & Science University in Portland, Oregon, told GI & Hepatology News.

While noting the limitation of the relatively small sample size, Qureshi said the study is nevertheless “exciting and moving the direction we want to go, specifically towards precision medicine [and] precision oncology.”

The study “builds on existing understanding, especially with regard to TP53 and CDH1, and it points to the opportunity to use this data in a way to direct patient care or possibly therapeutic intervention,” she said.

Laine’s disclosures include consulting and/or relationships with Medtronic, Phathom Pharmaceuticals, Biohaven, Celgene, Intercept Pharmaceuticals, Merck, and Pfizer. Qureshi had no disclosures to report.

A version of this article appeared on Medscape.com.

SAN DIEGO – Patients carrying at least one of the four key genes show a significantly increased risk for disease recurrence and mortality in gastric cancer, according to new research that potentially paves the way for precision oncology and improved targeting of therapies.

“About a third of patients with gastric cancer in our study had somatic mutations or variants of uncertain significance in [one of] four key genes,” lead author Ulysses Ribeiro, MD, PhD, a professor of digestive system surgery at the University of São Paulo School of Medicine in São Paulo, Brazil, said in a press briefing for the study, presented at Digestive Disease Week® (DDW) 2025.

“These patients were more likely to have their cancer come back or to die from the disease, even after surgery and the best chemotherapy and immunotherapy regimens,” said Ribeiro. While treatment strategies in gastric cancer have improved in recent years, resistance to multiple drugs continues, and the 5-year overall survival rate remains low — about 36% — underscoring the critical need for targeted therapies.

In an effort to identify genetic alterations that could have prognostic value, Ribeiro and his colleagues used next-generation DNA sequencing to analyze 21 genes in the tumor samples of 87 patients with gastric cancer who had undergone curative surgery and chemotherapy at the Sao Paulo Cancer Institute, São Paulo, Brazil.

Using Cox regression analysis, they found pathogenic variants or variants of uncertain significance in the following four genes: BRCA2, CDH1, RHOA, and TP53. “We found that 33% of patients carried at least one of these four genes,” Ribeiro told GI & Hepatology News.

Individually, each of the four genes with pathogenic variants or variants of uncertain significance had significantly or near-significantly higher risks in a survival analysis vs wild-type or benign variants, including BRCA2 (hazard ratio [HR], 4.33; P = .030); CDH1 (HR, 7.54; P = .004); RHOA (HR, 29.24; P < .001); and TP53 (HR, 2.82; P = .07).

A further multivariate analysis adjusting for key confounders showed that, when combined, carriers of the genes had lower disease-free survival (P = .005) and worse overall survival (P = .009) than those with none of the mutations.

“Individually, all four genes were related to prognosis in our gastric cancer patients, and when combined, the genes had even a higher difference in prognosis, varying from 2 to 28 times higher,” Ribeiro said.

Overall, factors such as having a more advanced tumor, node, metastasis stage, pathological stage, and the presence of a pathogenic mutation or a variant of uncertain significance in the four genes in the model were independently associated with worse disease-free survival.

 

Familiar Genes

Some of these genes are highly familiar. BRCA2 is well-known for its role in increasing the risk for breast and ovarian cancers, and CDH1 is known to be associated with hereditary diffuse gastric cancer, which is the most common hereditary cancer syndrome linked to gastric cancer.

TP53, also known as the “guardian of the genome,” is the most commonly altered gene in human cancers, while RHOA is known to be involved in encoding the GTPase protein RhoA, which is key in the regulation of cell shape, motility, and other essential cellular processes.

“This is the first time that these four genes have been shown to strongly relate to these gastric cancer outcomes,” said Ribeiro. This suggests that there’s more than one pathway by which stomach cancer forms and that some stomach cancers are much more aggressive than others.

He noted that “patients without these high-risk mutations” could be given “less aggressive treatment, in some cases sparing them from unnecessary side effects.”

Speaking during the press briefing, Loren A. Laine, MD, AGAF, who is a professor of medicine and chief of the Section of Digestive Diseases at the Yale School of Medicine in New Haven, Connecticut, and council chair of DDW 2025, agreed that “certainly, if these genetic factors, along with other factors, predict risk, this also has implications in practice with respect to the level of monitoring during the follow-up and determining the need for therapy.”

In addition, “it will be interesting to see how much this adds to other known risk factors, such as pathologic stage,” said Laine.

A strength of this study, “which I think is unique, is that it looks at a Western population,” whereas data on gastric as well as esophageal cancer is heavily biased to Eastern regions like China and East Asia, where the rates are much higher than in the West, Alia Qureshi, MD, an associate professor of esophageal and gastric cancer surgery at Oregon Health & Science University in Portland, Oregon, told GI & Hepatology News.

While noting the limitation of the relatively small sample size, Qureshi said the study is nevertheless “exciting and moving the direction we want to go, specifically towards precision medicine [and] precision oncology.”

The study “builds on existing understanding, especially with regard to TP53 and CDH1, and it points to the opportunity to use this data in a way to direct patient care or possibly therapeutic intervention,” she said.

Laine’s disclosures include consulting and/or relationships with Medtronic, Phathom Pharmaceuticals, Biohaven, Celgene, Intercept Pharmaceuticals, Merck, and Pfizer. Qureshi had no disclosures to report.

A version of this article appeared on Medscape.com.

SAN DIEGO — A 20-year initiative by Kaiser Permanente Northern California that assessed colorectal cancer (CRC) screening status and offered flexible options for screening has made a huge difference in CRC incidence, deaths, and racial disparities, an analysis showed.

“The program promptly doubled the proportion of people up to date with screening,” reported lead investigator Douglas A. Corley, MD, PhD, AGAF, a research scientist with Kaiser’s Division of Research, at a press briefing held on April 24, ahead of a presentation at the Digestive Disease Week® (DDW) 2025.

Additionally, within about 10 years, cancer rates were cut by a third, deaths were halved for the second most common cause of cancer deaths in the United States, and the differences that had previously been seen by race or ethnicity were largely eliminated, he said.

“Ten years ago, there were big gaps in cancer risk and death, especially among our Black patients. Now, those differences are nearly gone,” Corley said.

 

Closing the Gap

A systematic CRC screening program was implemented across Kaiser Permanente Northern California. The program included proactive outreach to members who were overdue for screening and mailing them fecal immunochemical test (FIT) kits for at-home use.

Corley and colleagues tracked screening status and CRC incidence and mortality annually from 2000 to 2019 among about 1.1 million members aged 50-75 years across 22 medical centers of the integrated healthcare system. The cohort included American Indian or Alaska Native, Asian, Black, Hispanic, Native Hawaiian or Pacific Islander, and White members.

Screening rates via FIT, colonoscopy, or sigmoidoscopy more than doubled after starting the program, from about 37% in the early years to about 80% within a few years, and it stayed that high through 2019, Corley reported. 

“Importantly, these large increases occurred across the whole population with only small differences,” he said. 

For example, about 76% of Hispanic members, 77% of Black members, 82% of White members, and 83% of Asian members were up to date in the later years and through 2019.

“This shows that systematic, comparable outreach can provide a level playing field for completion of preventive care,” Corley said.

After an expected early uptick in CRC incidence due to early detection, incidence later declined and by 2019 had dropped approximately 30% across the groups.

 

Long-Standing Disparities Erased

CRC deaths also fell by about 50% across all groups, with the largest decline among Black members, Corley noted.

Racial and ethnic disparities in both CRC incidence and mortality have long existed, with Black patients in particular experiencing higher risks and worse outcomes, likely from a mixture of risk factors and healthcare utilization, Corley said.

Offering outreach and equal access to screening in the Kaiser program erased those long-standing disparities.

“It’s remarkable that some of these large differences in mortality by race and ethnicity that we saw two decades ago, and which are found throughout the United States, are now similar to small chance variation in the population,” Corley said.

Flexibility was key to getting more people screened, he noted. “It’s about reaching people at their homes and offering a choice to patients. It’s an astonishingly simple concept.”

It’s important to note that these findings stem from a large, integrated healthcare system, which may differ from other settings, although similar outreach strategies have succeeded in safety net clinics and smaller practices, Corley added.

By boosting screening rates to 80%, the health system reached the level that’s essentially been defined in the past as our goal of screening programs, said Loren Laine, MD, AGAF, professor of medicine (digestive diseases) at Yale School of Medicine, New Haven, Connecticut, and chair of this year’s DDW. 

“It shows that if health systems institute programmatic screening for all their covered individuals, they could markedly increase screening, said Laine, who also served as moderator of the press briefing.

“Most importantly, of course, [screening] was associated with a reduction in colorectal cancer incidence and deaths,” he said.

The study had no commercial funding. Corley reported having no relevant conflicts of interest.

Laine’s disclosures included consulting and/or relationships with Medtronic, Phathom Pharmaceuticals, Biohaven, Celgene, Intercept, Merck, and Pfizer.

A version of this article appeared on Medscape.com.

SAN DIEGO — A 20-year initiative by Kaiser Permanente Northern California that assessed colorectal cancer (CRC) screening status and offered flexible options for screening has made a huge difference in CRC incidence, deaths, and racial disparities, an analysis showed.

“The program promptly doubled the proportion of people up to date with screening,” reported lead investigator Douglas A. Corley, MD, PhD, AGAF, a research scientist with Kaiser’s Division of Research, at a press briefing held on April 24, ahead of a presentation at the Digestive Disease Week® (DDW) 2025.

Additionally, within about 10 years, cancer rates were cut by a third, deaths were halved for the second most common cause of cancer deaths in the United States, and the differences that had previously been seen by race or ethnicity were largely eliminated, he said.

“Ten years ago, there were big gaps in cancer risk and death, especially among our Black patients. Now, those differences are nearly gone,” Corley said.

 

Closing the Gap

A systematic CRC screening program was implemented across Kaiser Permanente Northern California. The program included proactive outreach to members who were overdue for screening and mailing them fecal immunochemical test (FIT) kits for at-home use.

Corley and colleagues tracked screening status and CRC incidence and mortality annually from 2000 to 2019 among about 1.1 million members aged 50-75 years across 22 medical centers of the integrated healthcare system. The cohort included American Indian or Alaska Native, Asian, Black, Hispanic, Native Hawaiian or Pacific Islander, and White members.

Screening rates via FIT, colonoscopy, or sigmoidoscopy more than doubled after starting the program, from about 37% in the early years to about 80% within a few years, and it stayed that high through 2019, Corley reported. 

“Importantly, these large increases occurred across the whole population with only small differences,” he said. 

For example, about 76% of Hispanic members, 77% of Black members, 82% of White members, and 83% of Asian members were up to date in the later years and through 2019.

“This shows that systematic, comparable outreach can provide a level playing field for completion of preventive care,” Corley said.

After an expected early uptick in CRC incidence due to early detection, incidence later declined and by 2019 had dropped approximately 30% across the groups.

 

Long-Standing Disparities Erased

CRC deaths also fell by about 50% across all groups, with the largest decline among Black members, Corley noted.

Racial and ethnic disparities in both CRC incidence and mortality have long existed, with Black patients in particular experiencing higher risks and worse outcomes, likely from a mixture of risk factors and healthcare utilization, Corley said.

Offering outreach and equal access to screening in the Kaiser program erased those long-standing disparities.

“It’s remarkable that some of these large differences in mortality by race and ethnicity that we saw two decades ago, and which are found throughout the United States, are now similar to small chance variation in the population,” Corley said.

Flexibility was key to getting more people screened, he noted. “It’s about reaching people at their homes and offering a choice to patients. It’s an astonishingly simple concept.”

It’s important to note that these findings stem from a large, integrated healthcare system, which may differ from other settings, although similar outreach strategies have succeeded in safety net clinics and smaller practices, Corley added.

By boosting screening rates to 80%, the health system reached the level that’s essentially been defined in the past as our goal of screening programs, said Loren Laine, MD, AGAF, professor of medicine (digestive diseases) at Yale School of Medicine, New Haven, Connecticut, and chair of this year’s DDW. 

“It shows that if health systems institute programmatic screening for all their covered individuals, they could markedly increase screening, said Laine, who also served as moderator of the press briefing.

“Most importantly, of course, [screening] was associated with a reduction in colorectal cancer incidence and deaths,” he said.

The study had no commercial funding. Corley reported having no relevant conflicts of interest.

Laine’s disclosures included consulting and/or relationships with Medtronic, Phathom Pharmaceuticals, Biohaven, Celgene, Intercept, Merck, and Pfizer.

A version of this article appeared on Medscape.com.

SAN DIEGO — A 20-year initiative by Kaiser Permanente Northern California that assessed colorectal cancer (CRC) screening status and offered flexible options for screening has made a huge difference in CRC incidence, deaths, and racial disparities, an analysis showed.

“The program promptly doubled the proportion of people up to date with screening,” reported lead investigator Douglas A. Corley, MD, PhD, AGAF, a research scientist with Kaiser’s Division of Research, at a press briefing held on April 24, ahead of a presentation at the Digestive Disease Week® (DDW) 2025.

Additionally, within about 10 years, cancer rates were cut by a third, deaths were halved for the second most common cause of cancer deaths in the United States, and the differences that had previously been seen by race or ethnicity were largely eliminated, he said.

“Ten years ago, there were big gaps in cancer risk and death, especially among our Black patients. Now, those differences are nearly gone,” Corley said.

 

Closing the Gap

A systematic CRC screening program was implemented across Kaiser Permanente Northern California. The program included proactive outreach to members who were overdue for screening and mailing them fecal immunochemical test (FIT) kits for at-home use.

Corley and colleagues tracked screening status and CRC incidence and mortality annually from 2000 to 2019 among about 1.1 million members aged 50-75 years across 22 medical centers of the integrated healthcare system. The cohort included American Indian or Alaska Native, Asian, Black, Hispanic, Native Hawaiian or Pacific Islander, and White members.

Screening rates via FIT, colonoscopy, or sigmoidoscopy more than doubled after starting the program, from about 37% in the early years to about 80% within a few years, and it stayed that high through 2019, Corley reported. 

“Importantly, these large increases occurred across the whole population with only small differences,” he said. 

For example, about 76% of Hispanic members, 77% of Black members, 82% of White members, and 83% of Asian members were up to date in the later years and through 2019.

“This shows that systematic, comparable outreach can provide a level playing field for completion of preventive care,” Corley said.

After an expected early uptick in CRC incidence due to early detection, incidence later declined and by 2019 had dropped approximately 30% across the groups.

 

Long-Standing Disparities Erased

CRC deaths also fell by about 50% across all groups, with the largest decline among Black members, Corley noted.

Racial and ethnic disparities in both CRC incidence and mortality have long existed, with Black patients in particular experiencing higher risks and worse outcomes, likely from a mixture of risk factors and healthcare utilization, Corley said.

Offering outreach and equal access to screening in the Kaiser program erased those long-standing disparities.

“It’s remarkable that some of these large differences in mortality by race and ethnicity that we saw two decades ago, and which are found throughout the United States, are now similar to small chance variation in the population,” Corley said.

Flexibility was key to getting more people screened, he noted. “It’s about reaching people at their homes and offering a choice to patients. It’s an astonishingly simple concept.”

It’s important to note that these findings stem from a large, integrated healthcare system, which may differ from other settings, although similar outreach strategies have succeeded in safety net clinics and smaller practices, Corley added.

By boosting screening rates to 80%, the health system reached the level that’s essentially been defined in the past as our goal of screening programs, said Loren Laine, MD, AGAF, professor of medicine (digestive diseases) at Yale School of Medicine, New Haven, Connecticut, and chair of this year’s DDW. 

“It shows that if health systems institute programmatic screening for all their covered individuals, they could markedly increase screening, said Laine, who also served as moderator of the press briefing.

“Most importantly, of course, [screening] was associated with a reduction in colorectal cancer incidence and deaths,” he said.

The study had no commercial funding. Corley reported having no relevant conflicts of interest.

Laine’s disclosures included consulting and/or relationships with Medtronic, Phathom Pharmaceuticals, Biohaven, Celgene, Intercept, Merck, and Pfizer.

A version of this article appeared on Medscape.com.

WASHINGTON — When a published case of auto-brewery syndrome (ABS) in China — caused by Klebsiella pneumoniae — received widespread publicity in 2019, patients reacted, sending emails to lead author Jing Yuan, in Beijing, China. Many of these inquiries were from patients in the United States who believed they might have ABS.

“Can you check to see if I have ABS?” patients asked Yuan.

For help, Yuan contacted Bernd Schnabl, MD, AGAF, at the University of California, San Diego, whose research was addressing alcohol-associated liver disease and who was also interested in the gut-liver axis and the role of gut microbiome–derived ethanol in metabolic dysfunction–associated steatotic liver disease (MASLD).

“She asked me, ‘Are you interested in looking into ABS?” Schnabl recalled at the Gut Microbiota for Health (GMFH) World Summit 2025. He dug in and formed what may be the largest research cohort thus far of patients with ABS — a group of 22 patients with their diagnosis confirmed through observed glucose challenge.

His soon-to-be-published research on this cohort has confirmed excess ethanol production — and elevations of both proteobacteria and fermentation pathways — in patients whose ABS symptoms had flared.

ABS is considered a rare condition, but “I’d argue that it’s rarely diagnosed because many physicians don’t know of the diagnosis, and many are actually very skeptical about the disease,” Schnabl said at the meeting, convened by AGA and the European Society of Neurogastroenterology and Motility.

Patients experience symptoms of intoxication when ethanol produced by dysregulated gut microbiota exceeds the capacity of the liver to metabolize it and accumulates in the blood, he explained.

“Patients constantly talk about brain fog; they can’t concentrate, and it can be very severe,” he said. “They don’t get a firm diagnosis and go from one medical center to another, and they also suffer from complications of alcohol use disorder including serious family, social, and legal problems.”

 

Advancing Knowledge, Findings From the Cohort

The phenomenon of ethanol production by gut microbiota has been known for over a century, Schnabl wrote with two co-authors in a 2024 review in Nature Reviews Gastroenterology & Hepatology of “endogenous ethanol production in health and disease.”

And in recent decades, he said at the meeting, research has linked endogenous ethanol production to MASLD, positioning it as a potential contributor to disease pathogenesis. In one of the most recently published studies, patients with MASLD had higher concentrations of ethanol in their systemic circulation after a mixed meal test than did healthy controls — and even higher ethanol concentrations in their portal vein blood, “suggesting that this ethanol is coming from the gut microbiome,” Schnabl said.

The paper from China that led Schnabl to establish his cohort was spurred on by a patient with both ABS and MASLD cirrhosis. The patient was found to have strains of high alcohol–producing K pneumoniae in the gut microbiome. When the researchers transplanted these strains into mice via fecal microbiota transplantation (FMT), the mice developed MASLD.

Schnabl’s study focused just on ABS, which is alternatively sometimes called gut fermentation syndrome. The 22 patients in his ABS cohort — each of whom provided stool samples corresponding to remission or flare of ABS symptoms — had a median age of 45 years and were predominantly men, slightly overweight and not obese, and without liver disease. (About 48 patients with suspected ABS were screened, and 20 were excluded after an observed glucose challenge failed to establish a diagnosis; 6 withdrew from the study.)

During remission (no symptoms), patients’ mean blood alcohol content (BAC) level was zero, but during a flare, the mean BAC level was 136 mg/dL. “To put it into perspective, the legal limit for driving in the US is 80 mg/dL,” Schnabl said. Within a mean of 4 hours after the oral glucose load used for diagnosis, patients’ mean BAC level was 73 mg/dL, he noted.

To assess ethanol production by the patients’ microbiota, Schnabl and his team cultured the stool samples — anaerobically adding glucose and measuring ethanol production — and compared the results with findings from stool samples collected from household partners who generally were of the opposite sex. Among their findings: cultures of stool from patients experiencing a flare produced significantly more ethanol than stool from household partners and samples from patients in remission.

To assess whether ethanol was produced by bacteria or fungi, the researchers measured ethanol production in cultures treated with either the antifungal amphotericin B or the antibiotic chloramphenicol. “Chloramphenicol clearly decreased the ethanol production,” Schnabl said. “So at least in this culture test, bacteria produced most of the alcohol in our patients.”

Taxonomic profiling, moreover, revealed “significantly elevated levels” of proteobacteria — with relative abundance of Escherichia coli and K pneumoniae — in patients who were flaring, he said. And functional profiling of the fecal microbiota showed much higher activity of fermentation pathways during patients’ flares than in household partners or healthy controls. (Healthy controls were incorporated into the taxonomic and functional profiling parts of the research.)

 

A Clinical Approach to ABS

Schnabl said at the meeting that stool cultures of both household partners and patients in long-term remission “all produced some low amount of ethanol, which was initially puzzling to us” but became less surprising as he and his colleagues reviewed more of the literature.

Asked during a discussion period whether ABS could explain chronic fatigue, a commonly reported chronic symptom in populations, Schnabl said it’s possible. And in an interview after the meeting, he elaborated. “The literature clearly says ABS is a rare disease, but I argue that more patients may have ABS; they just don’t know it. And I suspect some may have mild symptoms, like brain fog, feeling tired,” he said. “But at this point, this is complete speculation.”

Physicians should “be aware that if a patient has unexplained symptoms that could be aligned with ABS, checking the blood alcohol level” may be warranted, he said in the interview. A PEth (phosphatidylethanol) test — a biomarker test used to check for longer-term alcohol consumption — is an option, but it is important to appreciate it will not discriminate between exogenous alcohol drinking and endogenous ethanol production.

There are no standardized diagnostic tests for ABS, but at the meeting, Schnabl outlined a clinical approach, starting with a standardized oral glucose tolerance challenge test to detect elevated ethanol concentrations.

A fecal yeast test is warranted for diagnosed patients on the basis of some case reports in which ABS symptoms have improved with antifungal treatments. When the fecal yeast test is negative, “ideally you want to identify the ethanol-producing intestinal bacteria in the patient,” he said, using cultures and fecal metagenomics sequencing.

Treatment could then be tailored to the identified microbial strain, with options being selective antibiotics, probiotics and/or prebiotics, and — likely in the future — phages or FMT, he said. (These options, all aimed at restoring gut homeostasis, are also discussed in his 2024 review.)

Schnabl and his team recently performed FMT in a patient with ABS in whom E coli was determined to be producing excessive ethanol. The FMT, performed after antibiotic pretreatment, resulted in decreases in the relative abundance of proteobacteria and E coli levels, lower blood alcohol levels and fermentation enrichment pathways, and normalized liver enzymes.

After 6 months, however, the patient relapsed, and the measurements reversed. “We decided to do FMT every month, and we treated the patient for 6 months,” Schnabl said, noting that ABS had rendered the patient dysfunctional and unable to work. “He has been out of treatment for over a year now and is not flaring any longer.”

Schnabl and Elizabeth Hohmann, MD, at Massachusetts General Hospital, Boston, are currently recruiting patients with confirmed ABS for a National Institutes of Health–funded phase 1 safety and tolerability study of FMT for ABS.

Schnabl disclosed serving as an external scientific advisor/consultant to Ambys Medicines, Boehringer Ingelheim, Gelesis, Mabwell Therapeutics, Surrozen, and Takeda; and as the founder/BOD/BEO of Nterica Bio.

A version of this article appeared on Medscape.com.

WASHINGTON — When a published case of auto-brewery syndrome (ABS) in China — caused by Klebsiella pneumoniae — received widespread publicity in 2019, patients reacted, sending emails to lead author Jing Yuan, in Beijing, China. Many of these inquiries were from patients in the United States who believed they might have ABS.

“Can you check to see if I have ABS?” patients asked Yuan.

For help, Yuan contacted Bernd Schnabl, MD, AGAF, at the University of California, San Diego, whose research was addressing alcohol-associated liver disease and who was also interested in the gut-liver axis and the role of gut microbiome–derived ethanol in metabolic dysfunction–associated steatotic liver disease (MASLD).

“She asked me, ‘Are you interested in looking into ABS?” Schnabl recalled at the Gut Microbiota for Health (GMFH) World Summit 2025. He dug in and formed what may be the largest research cohort thus far of patients with ABS — a group of 22 patients with their diagnosis confirmed through observed glucose challenge.

His soon-to-be-published research on this cohort has confirmed excess ethanol production — and elevations of both proteobacteria and fermentation pathways — in patients whose ABS symptoms had flared.

ABS is considered a rare condition, but “I’d argue that it’s rarely diagnosed because many physicians don’t know of the diagnosis, and many are actually very skeptical about the disease,” Schnabl said at the meeting, convened by AGA and the European Society of Neurogastroenterology and Motility.

Patients experience symptoms of intoxication when ethanol produced by dysregulated gut microbiota exceeds the capacity of the liver to metabolize it and accumulates in the blood, he explained.

“Patients constantly talk about brain fog; they can’t concentrate, and it can be very severe,” he said. “They don’t get a firm diagnosis and go from one medical center to another, and they also suffer from complications of alcohol use disorder including serious family, social, and legal problems.”

 

Advancing Knowledge, Findings From the Cohort

The phenomenon of ethanol production by gut microbiota has been known for over a century, Schnabl wrote with two co-authors in a 2024 review in Nature Reviews Gastroenterology & Hepatology of “endogenous ethanol production in health and disease.”

And in recent decades, he said at the meeting, research has linked endogenous ethanol production to MASLD, positioning it as a potential contributor to disease pathogenesis. In one of the most recently published studies, patients with MASLD had higher concentrations of ethanol in their systemic circulation after a mixed meal test than did healthy controls — and even higher ethanol concentrations in their portal vein blood, “suggesting that this ethanol is coming from the gut microbiome,” Schnabl said.

The paper from China that led Schnabl to establish his cohort was spurred on by a patient with both ABS and MASLD cirrhosis. The patient was found to have strains of high alcohol–producing K pneumoniae in the gut microbiome. When the researchers transplanted these strains into mice via fecal microbiota transplantation (FMT), the mice developed MASLD.

Schnabl’s study focused just on ABS, which is alternatively sometimes called gut fermentation syndrome. The 22 patients in his ABS cohort — each of whom provided stool samples corresponding to remission or flare of ABS symptoms — had a median age of 45 years and were predominantly men, slightly overweight and not obese, and without liver disease. (About 48 patients with suspected ABS were screened, and 20 were excluded after an observed glucose challenge failed to establish a diagnosis; 6 withdrew from the study.)

During remission (no symptoms), patients’ mean blood alcohol content (BAC) level was zero, but during a flare, the mean BAC level was 136 mg/dL. “To put it into perspective, the legal limit for driving in the US is 80 mg/dL,” Schnabl said. Within a mean of 4 hours after the oral glucose load used for diagnosis, patients’ mean BAC level was 73 mg/dL, he noted.

To assess ethanol production by the patients’ microbiota, Schnabl and his team cultured the stool samples — anaerobically adding glucose and measuring ethanol production — and compared the results with findings from stool samples collected from household partners who generally were of the opposite sex. Among their findings: cultures of stool from patients experiencing a flare produced significantly more ethanol than stool from household partners and samples from patients in remission.

To assess whether ethanol was produced by bacteria or fungi, the researchers measured ethanol production in cultures treated with either the antifungal amphotericin B or the antibiotic chloramphenicol. “Chloramphenicol clearly decreased the ethanol production,” Schnabl said. “So at least in this culture test, bacteria produced most of the alcohol in our patients.”

Taxonomic profiling, moreover, revealed “significantly elevated levels” of proteobacteria — with relative abundance of Escherichia coli and K pneumoniae — in patients who were flaring, he said. And functional profiling of the fecal microbiota showed much higher activity of fermentation pathways during patients’ flares than in household partners or healthy controls. (Healthy controls were incorporated into the taxonomic and functional profiling parts of the research.)

 

A Clinical Approach to ABS

Schnabl said at the meeting that stool cultures of both household partners and patients in long-term remission “all produced some low amount of ethanol, which was initially puzzling to us” but became less surprising as he and his colleagues reviewed more of the literature.

Asked during a discussion period whether ABS could explain chronic fatigue, a commonly reported chronic symptom in populations, Schnabl said it’s possible. And in an interview after the meeting, he elaborated. “The literature clearly says ABS is a rare disease, but I argue that more patients may have ABS; they just don’t know it. And I suspect some may have mild symptoms, like brain fog, feeling tired,” he said. “But at this point, this is complete speculation.”

Physicians should “be aware that if a patient has unexplained symptoms that could be aligned with ABS, checking the blood alcohol level” may be warranted, he said in the interview. A PEth (phosphatidylethanol) test — a biomarker test used to check for longer-term alcohol consumption — is an option, but it is important to appreciate it will not discriminate between exogenous alcohol drinking and endogenous ethanol production.

There are no standardized diagnostic tests for ABS, but at the meeting, Schnabl outlined a clinical approach, starting with a standardized oral glucose tolerance challenge test to detect elevated ethanol concentrations.

A fecal yeast test is warranted for diagnosed patients on the basis of some case reports in which ABS symptoms have improved with antifungal treatments. When the fecal yeast test is negative, “ideally you want to identify the ethanol-producing intestinal bacteria in the patient,” he said, using cultures and fecal metagenomics sequencing.

Treatment could then be tailored to the identified microbial strain, with options being selective antibiotics, probiotics and/or prebiotics, and — likely in the future — phages or FMT, he said. (These options, all aimed at restoring gut homeostasis, are also discussed in his 2024 review.)

Schnabl and his team recently performed FMT in a patient with ABS in whom E coli was determined to be producing excessive ethanol. The FMT, performed after antibiotic pretreatment, resulted in decreases in the relative abundance of proteobacteria and E coli levels, lower blood alcohol levels and fermentation enrichment pathways, and normalized liver enzymes.

After 6 months, however, the patient relapsed, and the measurements reversed. “We decided to do FMT every month, and we treated the patient for 6 months,” Schnabl said, noting that ABS had rendered the patient dysfunctional and unable to work. “He has been out of treatment for over a year now and is not flaring any longer.”

Schnabl and Elizabeth Hohmann, MD, at Massachusetts General Hospital, Boston, are currently recruiting patients with confirmed ABS for a National Institutes of Health–funded phase 1 safety and tolerability study of FMT for ABS.

Schnabl disclosed serving as an external scientific advisor/consultant to Ambys Medicines, Boehringer Ingelheim, Gelesis, Mabwell Therapeutics, Surrozen, and Takeda; and as the founder/BOD/BEO of Nterica Bio.

A version of this article appeared on Medscape.com.

WASHINGTON — When a published case of auto-brewery syndrome (ABS) in China — caused by Klebsiella pneumoniae — received widespread publicity in 2019, patients reacted, sending emails to lead author Jing Yuan, in Beijing, China. Many of these inquiries were from patients in the United States who believed they might have ABS.

“Can you check to see if I have ABS?” patients asked Yuan.

For help, Yuan contacted Bernd Schnabl, MD, AGAF, at the University of California, San Diego, whose research was addressing alcohol-associated liver disease and who was also interested in the gut-liver axis and the role of gut microbiome–derived ethanol in metabolic dysfunction–associated steatotic liver disease (MASLD).

“She asked me, ‘Are you interested in looking into ABS?” Schnabl recalled at the Gut Microbiota for Health (GMFH) World Summit 2025. He dug in and formed what may be the largest research cohort thus far of patients with ABS — a group of 22 patients with their diagnosis confirmed through observed glucose challenge.

His soon-to-be-published research on this cohort has confirmed excess ethanol production — and elevations of both proteobacteria and fermentation pathways — in patients whose ABS symptoms had flared.

ABS is considered a rare condition, but “I’d argue that it’s rarely diagnosed because many physicians don’t know of the diagnosis, and many are actually very skeptical about the disease,” Schnabl said at the meeting, convened by AGA and the European Society of Neurogastroenterology and Motility.

Patients experience symptoms of intoxication when ethanol produced by dysregulated gut microbiota exceeds the capacity of the liver to metabolize it and accumulates in the blood, he explained.

“Patients constantly talk about brain fog; they can’t concentrate, and it can be very severe,” he said. “They don’t get a firm diagnosis and go from one medical center to another, and they also suffer from complications of alcohol use disorder including serious family, social, and legal problems.”

 

Advancing Knowledge, Findings From the Cohort

The phenomenon of ethanol production by gut microbiota has been known for over a century, Schnabl wrote with two co-authors in a 2024 review in Nature Reviews Gastroenterology & Hepatology of “endogenous ethanol production in health and disease.”

And in recent decades, he said at the meeting, research has linked endogenous ethanol production to MASLD, positioning it as a potential contributor to disease pathogenesis. In one of the most recently published studies, patients with MASLD had higher concentrations of ethanol in their systemic circulation after a mixed meal test than did healthy controls — and even higher ethanol concentrations in their portal vein blood, “suggesting that this ethanol is coming from the gut microbiome,” Schnabl said.

The paper from China that led Schnabl to establish his cohort was spurred on by a patient with both ABS and MASLD cirrhosis. The patient was found to have strains of high alcohol–producing K pneumoniae in the gut microbiome. When the researchers transplanted these strains into mice via fecal microbiota transplantation (FMT), the mice developed MASLD.

Schnabl’s study focused just on ABS, which is alternatively sometimes called gut fermentation syndrome. The 22 patients in his ABS cohort — each of whom provided stool samples corresponding to remission or flare of ABS symptoms — had a median age of 45 years and were predominantly men, slightly overweight and not obese, and without liver disease. (About 48 patients with suspected ABS were screened, and 20 were excluded after an observed glucose challenge failed to establish a diagnosis; 6 withdrew from the study.)

During remission (no symptoms), patients’ mean blood alcohol content (BAC) level was zero, but during a flare, the mean BAC level was 136 mg/dL. “To put it into perspective, the legal limit for driving in the US is 80 mg/dL,” Schnabl said. Within a mean of 4 hours after the oral glucose load used for diagnosis, patients’ mean BAC level was 73 mg/dL, he noted.

To assess ethanol production by the patients’ microbiota, Schnabl and his team cultured the stool samples — anaerobically adding glucose and measuring ethanol production — and compared the results with findings from stool samples collected from household partners who generally were of the opposite sex. Among their findings: cultures of stool from patients experiencing a flare produced significantly more ethanol than stool from household partners and samples from patients in remission.

To assess whether ethanol was produced by bacteria or fungi, the researchers measured ethanol production in cultures treated with either the antifungal amphotericin B or the antibiotic chloramphenicol. “Chloramphenicol clearly decreased the ethanol production,” Schnabl said. “So at least in this culture test, bacteria produced most of the alcohol in our patients.”

Taxonomic profiling, moreover, revealed “significantly elevated levels” of proteobacteria — with relative abundance of Escherichia coli and K pneumoniae — in patients who were flaring, he said. And functional profiling of the fecal microbiota showed much higher activity of fermentation pathways during patients’ flares than in household partners or healthy controls. (Healthy controls were incorporated into the taxonomic and functional profiling parts of the research.)

 

A Clinical Approach to ABS

Schnabl said at the meeting that stool cultures of both household partners and patients in long-term remission “all produced some low amount of ethanol, which was initially puzzling to us” but became less surprising as he and his colleagues reviewed more of the literature.

Asked during a discussion period whether ABS could explain chronic fatigue, a commonly reported chronic symptom in populations, Schnabl said it’s possible. And in an interview after the meeting, he elaborated. “The literature clearly says ABS is a rare disease, but I argue that more patients may have ABS; they just don’t know it. And I suspect some may have mild symptoms, like brain fog, feeling tired,” he said. “But at this point, this is complete speculation.”

Physicians should “be aware that if a patient has unexplained symptoms that could be aligned with ABS, checking the blood alcohol level” may be warranted, he said in the interview. A PEth (phosphatidylethanol) test — a biomarker test used to check for longer-term alcohol consumption — is an option, but it is important to appreciate it will not discriminate between exogenous alcohol drinking and endogenous ethanol production.

There are no standardized diagnostic tests for ABS, but at the meeting, Schnabl outlined a clinical approach, starting with a standardized oral glucose tolerance challenge test to detect elevated ethanol concentrations.

A fecal yeast test is warranted for diagnosed patients on the basis of some case reports in which ABS symptoms have improved with antifungal treatments. When the fecal yeast test is negative, “ideally you want to identify the ethanol-producing intestinal bacteria in the patient,” he said, using cultures and fecal metagenomics sequencing.

Treatment could then be tailored to the identified microbial strain, with options being selective antibiotics, probiotics and/or prebiotics, and — likely in the future — phages or FMT, he said. (These options, all aimed at restoring gut homeostasis, are also discussed in his 2024 review.)

Schnabl and his team recently performed FMT in a patient with ABS in whom E coli was determined to be producing excessive ethanol. The FMT, performed after antibiotic pretreatment, resulted in decreases in the relative abundance of proteobacteria and E coli levels, lower blood alcohol levels and fermentation enrichment pathways, and normalized liver enzymes.

After 6 months, however, the patient relapsed, and the measurements reversed. “We decided to do FMT every month, and we treated the patient for 6 months,” Schnabl said, noting that ABS had rendered the patient dysfunctional and unable to work. “He has been out of treatment for over a year now and is not flaring any longer.”

Schnabl and Elizabeth Hohmann, MD, at Massachusetts General Hospital, Boston, are currently recruiting patients with confirmed ABS for a National Institutes of Health–funded phase 1 safety and tolerability study of FMT for ABS.

Schnabl disclosed serving as an external scientific advisor/consultant to Ambys Medicines, Boehringer Ingelheim, Gelesis, Mabwell Therapeutics, Surrozen, and Takeda; and as the founder/BOD/BEO of Nterica Bio.

A version of this article appeared on Medscape.com.

WASHINGTON, DC — Research on the gut microbiome — and clinical attention to it — has focused mainly on bacteria, but bacteriophages and fungi play critical roles as well, with significant influences on health and disease, experts said at the Gut Microbiota for Health (GMFH) World Summit 2025.

Fungi account for < 1% of the total genetic material in the microbiome but 1%-2% of its total biomass. “Despite their relative rarity, they have an important and outsized influence on gut health” — an impact that results from their unique interface with the immune system, said Kyla Ost, PhD, of the Anschutz Medical Campus, University of Colorado, in Denver, whose research focuses on this interface.

And bacteriophages — viruses that infect and kill bacteria — are highly abundant in the gut. “Bacteriophages begin to colonize our GI [gastrointestinal] tract at the same time we develop our own microbiome shortly after birth, and from that time on, they interact with the bacteria in our GI tract, shaping [and being shaped by] the bacterial species we carry with us,” said Robert (Chip) Schooley, MD, distinguished professor of medicine at the University of California San Diego School of Medicine.

“We’ve been talking about things that affect the gut microbiome — diet, genetics, immune response — but probably the biggest influence on what grows in the GI tract are bacteriophages,” said Schooley, co-director of the Center for Innovative Phage Applications and Therapeutics, in a session on the extra-bacterial gut ecosystem.

Among the current questions: How can phages be used to manipulate the gut microbiome and influence GI-related diseases? And how can the pathogenic potential of commensal fungi be limited?

 

‘New life’ for Phage Therapy

Bacteriophages represent a promising approach for the treatment of multidrug resistant bacterial pathogens in an era of increasing resistance and a dried-up antibiotic discovery pipeline, Schooley said. (In 2019, an estimated 4.95 million deaths around the world were associated with bacterial antimicrobial resistance, and by 2050, it has been forecast that this number will rise to an estimated 8.22 million deaths.)

But in addition to suppressing bacterial pathogens causing direct morbidity, phage therapy has the potential to suppress bacteria believed to contribute to chronic diseases, he said. “We have proof-of-concept studies about the ability of phage to modulate bacteria in the digestive tract,” and an increasing number of clinical trials of the use of phages in GI and other diseases are underway, he said.

Phages were discovered just over a century ago, but phage therapy was widely abandoned once antibiotics were developed, except for in Russia and the former Eastern Bloc countries, where phage therapy continued to be used.

Phage therapy “got new life” in the West, Schooley said, about 10-15 years ago with an increasing number of detailed and high-profile case reports, including one in which a UC San Diego colleague, Tom Patterson, PhD, contracted a deadly multidrug resistant bacterial infection in Egypt and was eventually saved with bacteriophage therapy. (The case was the subject of the book The Perfect Predator).

Since then, as described in case reports and studies in the literature, “hundreds of people have been treated with bacteriophages here and in Europe,” most commonly for pulmonary infections and infections in implanted vascular and orthopedic devices, said Schooley, who coauthored a review in Cell in 2023 that describes phage biology and advances and future directions in phage therapy.

The use of bacteriophages to prevent systemic infections during high-risk periods — such as during chemotherapeutic regimens for hematological regimens — is an area of interest, he said at the meeting.

In research that is making its way to a clinical trial of patients undergoing allogeneic hematopoietic stem cell transplant (HSCT), researchers screened a library of phages to identify those with broad coverage of Escherichia coli. Using tail fiber engineering and CRISPR technology, they then engineered a combination of the four most complementary bacteriophages to selectively kill E coli — including fluoroquinolone-resistant strains that, in patients whose GI tracts are colonized with these strains, can translocate from the gut into the bloodstream, causing sepsis, during chemotherapeutic regimens for HSCT.

In a mouse model, the CRISPR-enhanced four-phage cocktail (SNIPR001) led to a steady reduction in the E coli colony counts in stool, “showing you can modulate these bacteria in the gut by using bacteriophages to kill them,” Schooley said. Moreover, the CRISPR enhancement strengthened the phages’ ability to break up biofilms, he said, showing “that you can engineer bacteriophages to make them better killers.” A phase 1b/2a study is being planned.

 

Other Niches for Therapeutic Phages, Challenges

Bacteriophages also could be used to target a gut bacterium that has been shown to attenuate alcoholic liver disease. Patients with alcoholic hepatitis “have a gut microbiome that is different in distribution,” Schooley said, often with increased numbers of Enterococcus faecalis that produce cytolysin, an exotoxin that exacerbates liver injury and is associated with increased mortality.

In published research led by investigators at UC San Diego, stool from cytolysin-positive patients with alcoholic hepatitis was found to exacerbate ethanol-induced liver disease in gnotobiotic mice, and phage therapy against cytolytic E faecalis was found to abolish it, Schooley shared.

Research is also exploring the potential of phage therapy to selectively target adherent invasive E coli in Crohn’s disease, and Klebsiella pneumoniae in the gut microbiome as an exacerbator of inflammatory bowel disease (IBD), he said.

And investigators in Japan, he noted, have reported that bacteriophage therapy against K pneumoniae can ameliorate liver inflammation and disease severity in primary sclerosing cholangitis.

Challenges in the therapeutic use of phages include the narrow host range of phages and an uncertain predictive value of in vitro phage susceptibility testing. “We don’t know yet how to do resistance testing as well as we do with antibiotics,” he said.

In addition, most phages tend to be acid labile, requiring strategies to mitigate inactivation by gastric acid, and there are “major knowledge gaps” relating to phage pharmacology. “We also know that adaptive immune responses to phages can but often doesn’t impact therapy, and we want to understand that better in clinical trials,” Schooley said.

Phages that have a “lysogenic” lifestyle — as opposed to lytic phages which are used therapeutically — can contribute to antibiotic resistance by facilitating the interchange of bacterial resistance genes, he noted.

 

A Window Into the Mycobiome

The human gut mycobiome is primarily composed of fungi in the Saccharomyces, Candida, and Malassezia genera, with Candida species dominating. Fungal cells harbor distinct immune-stimulatory molecules and activate distinct immune pathways compared with bacteria and other members of the microbiome, said Ost, assistant professor in the immunology and microbiology department of CU Anschutz.

Some fungi, including those in the Candida genus, activate adaptive and innate immune responses that promote metabolic health and protect against infection. A recently published study in Science, for instance, demonstrated that colonization with C dubliniensis in very young mice who had been exposed to broad-spectrum antibiotics promoted “the expansion and development of beta cells in the pancreas” in a macrophage dependent manner, improving metabolic health and reducing diabetes incidence, she shared.

On the one hand, fungi can “exacerbate and perpetuate the pathogenic inflammation that’s found in a growing list of inflammatory diseases” such as IBD. And “in fact, a lot of the benefits and detriments are driven by the exact same species of fungi,” said Ost. “This is particularly true of Candida,” which is a “lifelong colonizer of intestinal microbiota that rarely causes disease but can be quite pathogenic when it does.”

A 2023 review in Nature Reviews Gastroenterology & Hepatology coauthored by Ost describes the role of commensal fungi in intestinal diseases, including IBD, colorectal cancer, and pancreatic cancer.

The pathogenic potential of commensal fungi is largely dependent on its strain, its morphology and its expression of virulence factors, researchers are learning. Ost has studied C albicans, which has been associated with intestinal inflammation and IBD. Like some other Candida species, C albicans are “fascinating shape shifters,” she said, transitioning between a less pathogenic “yeast” morphology and an elongated, adhesive “hyphae” shape that is more pathogenic.

It turns out, according to research by Ost and others, that the C albicans hyphal morphotype — and the adhesins (sticky proteins that facilitate adherence to epithelial cells) and a cytolytic toxin it produces — are preferentially targeted and suppressed by immunoglobulin A (IgA) in the gut.

“Our gut is protected by a large quantity of IgA antibodies…and these IgA interact with the microbiota and play a big role in what microbes are there and the biology of the microbes,” Ost said. Indeed, symptomatic IgA deficiency in humans has been shown to be associated with C albicans overgrowth.

Leveraging the hyphal-specific IgA response to protect against disease seems possible, she said, referring to an experimental anti-Candida fungal vaccine (NDV-3A) designed to induce an adhesin-specific immune response. In a mouse model of colitis, the vaccine protected against C albicans-associated damage. “We saw an immediate IgA response that targeted C albicans in the intestinal contents,” Ost said.

C glabrata, which has also been associated with intestinal inflammation and IBD, does not form hyphae but — depending on the strain — may also induce intestinal IgA responses, she said in describing her recent research.

Ost reported having no disclosures. Schooley disclosed being a consultant for SNIPR Biome, BiomX, Locus, MicrobiotiX, Amazon Data Monitoring Committee: Merck.

A version of this article appeared on Medscape.com.

WASHINGTON, DC — Research on the gut microbiome — and clinical attention to it — has focused mainly on bacteria, but bacteriophages and fungi play critical roles as well, with significant influences on health and disease, experts said at the Gut Microbiota for Health (GMFH) World Summit 2025.

Fungi account for < 1% of the total genetic material in the microbiome but 1%-2% of its total biomass. “Despite their relative rarity, they have an important and outsized influence on gut health” — an impact that results from their unique interface with the immune system, said Kyla Ost, PhD, of the Anschutz Medical Campus, University of Colorado, in Denver, whose research focuses on this interface.

And bacteriophages — viruses that infect and kill bacteria — are highly abundant in the gut. “Bacteriophages begin to colonize our GI [gastrointestinal] tract at the same time we develop our own microbiome shortly after birth, and from that time on, they interact with the bacteria in our GI tract, shaping [and being shaped by] the bacterial species we carry with us,” said Robert (Chip) Schooley, MD, distinguished professor of medicine at the University of California San Diego School of Medicine.

“We’ve been talking about things that affect the gut microbiome — diet, genetics, immune response — but probably the biggest influence on what grows in the GI tract are bacteriophages,” said Schooley, co-director of the Center for Innovative Phage Applications and Therapeutics, in a session on the extra-bacterial gut ecosystem.

Among the current questions: How can phages be used to manipulate the gut microbiome and influence GI-related diseases? And how can the pathogenic potential of commensal fungi be limited?

 

‘New life’ for Phage Therapy

Bacteriophages represent a promising approach for the treatment of multidrug resistant bacterial pathogens in an era of increasing resistance and a dried-up antibiotic discovery pipeline, Schooley said. (In 2019, an estimated 4.95 million deaths around the world were associated with bacterial antimicrobial resistance, and by 2050, it has been forecast that this number will rise to an estimated 8.22 million deaths.)

But in addition to suppressing bacterial pathogens causing direct morbidity, phage therapy has the potential to suppress bacteria believed to contribute to chronic diseases, he said. “We have proof-of-concept studies about the ability of phage to modulate bacteria in the digestive tract,” and an increasing number of clinical trials of the use of phages in GI and other diseases are underway, he said.

Phages were discovered just over a century ago, but phage therapy was widely abandoned once antibiotics were developed, except for in Russia and the former Eastern Bloc countries, where phage therapy continued to be used.

Phage therapy “got new life” in the West, Schooley said, about 10-15 years ago with an increasing number of detailed and high-profile case reports, including one in which a UC San Diego colleague, Tom Patterson, PhD, contracted a deadly multidrug resistant bacterial infection in Egypt and was eventually saved with bacteriophage therapy. (The case was the subject of the book The Perfect Predator).

Since then, as described in case reports and studies in the literature, “hundreds of people have been treated with bacteriophages here and in Europe,” most commonly for pulmonary infections and infections in implanted vascular and orthopedic devices, said Schooley, who coauthored a review in Cell in 2023 that describes phage biology and advances and future directions in phage therapy.

The use of bacteriophages to prevent systemic infections during high-risk periods — such as during chemotherapeutic regimens for hematological regimens — is an area of interest, he said at the meeting.

In research that is making its way to a clinical trial of patients undergoing allogeneic hematopoietic stem cell transplant (HSCT), researchers screened a library of phages to identify those with broad coverage of Escherichia coli. Using tail fiber engineering and CRISPR technology, they then engineered a combination of the four most complementary bacteriophages to selectively kill E coli — including fluoroquinolone-resistant strains that, in patients whose GI tracts are colonized with these strains, can translocate from the gut into the bloodstream, causing sepsis, during chemotherapeutic regimens for HSCT.

In a mouse model, the CRISPR-enhanced four-phage cocktail (SNIPR001) led to a steady reduction in the E coli colony counts in stool, “showing you can modulate these bacteria in the gut by using bacteriophages to kill them,” Schooley said. Moreover, the CRISPR enhancement strengthened the phages’ ability to break up biofilms, he said, showing “that you can engineer bacteriophages to make them better killers.” A phase 1b/2a study is being planned.

 

Other Niches for Therapeutic Phages, Challenges

Bacteriophages also could be used to target a gut bacterium that has been shown to attenuate alcoholic liver disease. Patients with alcoholic hepatitis “have a gut microbiome that is different in distribution,” Schooley said, often with increased numbers of Enterococcus faecalis that produce cytolysin, an exotoxin that exacerbates liver injury and is associated with increased mortality.

In published research led by investigators at UC San Diego, stool from cytolysin-positive patients with alcoholic hepatitis was found to exacerbate ethanol-induced liver disease in gnotobiotic mice, and phage therapy against cytolytic E faecalis was found to abolish it, Schooley shared.

Research is also exploring the potential of phage therapy to selectively target adherent invasive E coli in Crohn’s disease, and Klebsiella pneumoniae in the gut microbiome as an exacerbator of inflammatory bowel disease (IBD), he said.

And investigators in Japan, he noted, have reported that bacteriophage therapy against K pneumoniae can ameliorate liver inflammation and disease severity in primary sclerosing cholangitis.

Challenges in the therapeutic use of phages include the narrow host range of phages and an uncertain predictive value of in vitro phage susceptibility testing. “We don’t know yet how to do resistance testing as well as we do with antibiotics,” he said.

In addition, most phages tend to be acid labile, requiring strategies to mitigate inactivation by gastric acid, and there are “major knowledge gaps” relating to phage pharmacology. “We also know that adaptive immune responses to phages can but often doesn’t impact therapy, and we want to understand that better in clinical trials,” Schooley said.

Phages that have a “lysogenic” lifestyle — as opposed to lytic phages which are used therapeutically — can contribute to antibiotic resistance by facilitating the interchange of bacterial resistance genes, he noted.

 

A Window Into the Mycobiome

The human gut mycobiome is primarily composed of fungi in the Saccharomyces, Candida, and Malassezia genera, with Candida species dominating. Fungal cells harbor distinct immune-stimulatory molecules and activate distinct immune pathways compared with bacteria and other members of the microbiome, said Ost, assistant professor in the immunology and microbiology department of CU Anschutz.

Some fungi, including those in the Candida genus, activate adaptive and innate immune responses that promote metabolic health and protect against infection. A recently published study in Science, for instance, demonstrated that colonization with C dubliniensis in very young mice who had been exposed to broad-spectrum antibiotics promoted “the expansion and development of beta cells in the pancreas” in a macrophage dependent manner, improving metabolic health and reducing diabetes incidence, she shared.

On the one hand, fungi can “exacerbate and perpetuate the pathogenic inflammation that’s found in a growing list of inflammatory diseases” such as IBD. And “in fact, a lot of the benefits and detriments are driven by the exact same species of fungi,” said Ost. “This is particularly true of Candida,” which is a “lifelong colonizer of intestinal microbiota that rarely causes disease but can be quite pathogenic when it does.”

A 2023 review in Nature Reviews Gastroenterology & Hepatology coauthored by Ost describes the role of commensal fungi in intestinal diseases, including IBD, colorectal cancer, and pancreatic cancer.

The pathogenic potential of commensal fungi is largely dependent on its strain, its morphology and its expression of virulence factors, researchers are learning. Ost has studied C albicans, which has been associated with intestinal inflammation and IBD. Like some other Candida species, C albicans are “fascinating shape shifters,” she said, transitioning between a less pathogenic “yeast” morphology and an elongated, adhesive “hyphae” shape that is more pathogenic.

It turns out, according to research by Ost and others, that the C albicans hyphal morphotype — and the adhesins (sticky proteins that facilitate adherence to epithelial cells) and a cytolytic toxin it produces — are preferentially targeted and suppressed by immunoglobulin A (IgA) in the gut.

“Our gut is protected by a large quantity of IgA antibodies…and these IgA interact with the microbiota and play a big role in what microbes are there and the biology of the microbes,” Ost said. Indeed, symptomatic IgA deficiency in humans has been shown to be associated with C albicans overgrowth.

Leveraging the hyphal-specific IgA response to protect against disease seems possible, she said, referring to an experimental anti-Candida fungal vaccine (NDV-3A) designed to induce an adhesin-specific immune response. In a mouse model of colitis, the vaccine protected against C albicans-associated damage. “We saw an immediate IgA response that targeted C albicans in the intestinal contents,” Ost said.

C glabrata, which has also been associated with intestinal inflammation and IBD, does not form hyphae but — depending on the strain — may also induce intestinal IgA responses, she said in describing her recent research.

Ost reported having no disclosures. Schooley disclosed being a consultant for SNIPR Biome, BiomX, Locus, MicrobiotiX, Amazon Data Monitoring Committee: Merck.

A version of this article appeared on Medscape.com.

WASHINGTON, DC — Research on the gut microbiome — and clinical attention to it — has focused mainly on bacteria, but bacteriophages and fungi play critical roles as well, with significant influences on health and disease, experts said at the Gut Microbiota for Health (GMFH) World Summit 2025.

Fungi account for < 1% of the total genetic material in the microbiome but 1%-2% of its total biomass. “Despite their relative rarity, they have an important and outsized influence on gut health” — an impact that results from their unique interface with the immune system, said Kyla Ost, PhD, of the Anschutz Medical Campus, University of Colorado, in Denver, whose research focuses on this interface.

And bacteriophages — viruses that infect and kill bacteria — are highly abundant in the gut. “Bacteriophages begin to colonize our GI [gastrointestinal] tract at the same time we develop our own microbiome shortly after birth, and from that time on, they interact with the bacteria in our GI tract, shaping [and being shaped by] the bacterial species we carry with us,” said Robert (Chip) Schooley, MD, distinguished professor of medicine at the University of California San Diego School of Medicine.

“We’ve been talking about things that affect the gut microbiome — diet, genetics, immune response — but probably the biggest influence on what grows in the GI tract are bacteriophages,” said Schooley, co-director of the Center for Innovative Phage Applications and Therapeutics, in a session on the extra-bacterial gut ecosystem.

Among the current questions: How can phages be used to manipulate the gut microbiome and influence GI-related diseases? And how can the pathogenic potential of commensal fungi be limited?

 

‘New life’ for Phage Therapy

Bacteriophages represent a promising approach for the treatment of multidrug resistant bacterial pathogens in an era of increasing resistance and a dried-up antibiotic discovery pipeline, Schooley said. (In 2019, an estimated 4.95 million deaths around the world were associated with bacterial antimicrobial resistance, and by 2050, it has been forecast that this number will rise to an estimated 8.22 million deaths.)

But in addition to suppressing bacterial pathogens causing direct morbidity, phage therapy has the potential to suppress bacteria believed to contribute to chronic diseases, he said. “We have proof-of-concept studies about the ability of phage to modulate bacteria in the digestive tract,” and an increasing number of clinical trials of the use of phages in GI and other diseases are underway, he said.

Phages were discovered just over a century ago, but phage therapy was widely abandoned once antibiotics were developed, except for in Russia and the former Eastern Bloc countries, where phage therapy continued to be used.

Phage therapy “got new life” in the West, Schooley said, about 10-15 years ago with an increasing number of detailed and high-profile case reports, including one in which a UC San Diego colleague, Tom Patterson, PhD, contracted a deadly multidrug resistant bacterial infection in Egypt and was eventually saved with bacteriophage therapy. (The case was the subject of the book The Perfect Predator).

Since then, as described in case reports and studies in the literature, “hundreds of people have been treated with bacteriophages here and in Europe,” most commonly for pulmonary infections and infections in implanted vascular and orthopedic devices, said Schooley, who coauthored a review in Cell in 2023 that describes phage biology and advances and future directions in phage therapy.

The use of bacteriophages to prevent systemic infections during high-risk periods — such as during chemotherapeutic regimens for hematological regimens — is an area of interest, he said at the meeting.

In research that is making its way to a clinical trial of patients undergoing allogeneic hematopoietic stem cell transplant (HSCT), researchers screened a library of phages to identify those with broad coverage of Escherichia coli. Using tail fiber engineering and CRISPR technology, they then engineered a combination of the four most complementary bacteriophages to selectively kill E coli — including fluoroquinolone-resistant strains that, in patients whose GI tracts are colonized with these strains, can translocate from the gut into the bloodstream, causing sepsis, during chemotherapeutic regimens for HSCT.

In a mouse model, the CRISPR-enhanced four-phage cocktail (SNIPR001) led to a steady reduction in the E coli colony counts in stool, “showing you can modulate these bacteria in the gut by using bacteriophages to kill them,” Schooley said. Moreover, the CRISPR enhancement strengthened the phages’ ability to break up biofilms, he said, showing “that you can engineer bacteriophages to make them better killers.” A phase 1b/2a study is being planned.

 

Other Niches for Therapeutic Phages, Challenges

Bacteriophages also could be used to target a gut bacterium that has been shown to attenuate alcoholic liver disease. Patients with alcoholic hepatitis “have a gut microbiome that is different in distribution,” Schooley said, often with increased numbers of Enterococcus faecalis that produce cytolysin, an exotoxin that exacerbates liver injury and is associated with increased mortality.

In published research led by investigators at UC San Diego, stool from cytolysin-positive patients with alcoholic hepatitis was found to exacerbate ethanol-induced liver disease in gnotobiotic mice, and phage therapy against cytolytic E faecalis was found to abolish it, Schooley shared.

Research is also exploring the potential of phage therapy to selectively target adherent invasive E coli in Crohn’s disease, and Klebsiella pneumoniae in the gut microbiome as an exacerbator of inflammatory bowel disease (IBD), he said.

And investigators in Japan, he noted, have reported that bacteriophage therapy against K pneumoniae can ameliorate liver inflammation and disease severity in primary sclerosing cholangitis.

Challenges in the therapeutic use of phages include the narrow host range of phages and an uncertain predictive value of in vitro phage susceptibility testing. “We don’t know yet how to do resistance testing as well as we do with antibiotics,” he said.

In addition, most phages tend to be acid labile, requiring strategies to mitigate inactivation by gastric acid, and there are “major knowledge gaps” relating to phage pharmacology. “We also know that adaptive immune responses to phages can but often doesn’t impact therapy, and we want to understand that better in clinical trials,” Schooley said.

Phages that have a “lysogenic” lifestyle — as opposed to lytic phages which are used therapeutically — can contribute to antibiotic resistance by facilitating the interchange of bacterial resistance genes, he noted.

 

A Window Into the Mycobiome

The human gut mycobiome is primarily composed of fungi in the Saccharomyces, Candida, and Malassezia genera, with Candida species dominating. Fungal cells harbor distinct immune-stimulatory molecules and activate distinct immune pathways compared with bacteria and other members of the microbiome, said Ost, assistant professor in the immunology and microbiology department of CU Anschutz.

Some fungi, including those in the Candida genus, activate adaptive and innate immune responses that promote metabolic health and protect against infection. A recently published study in Science, for instance, demonstrated that colonization with C dubliniensis in very young mice who had been exposed to broad-spectrum antibiotics promoted “the expansion and development of beta cells in the pancreas” in a macrophage dependent manner, improving metabolic health and reducing diabetes incidence, she shared.

On the one hand, fungi can “exacerbate and perpetuate the pathogenic inflammation that’s found in a growing list of inflammatory diseases” such as IBD. And “in fact, a lot of the benefits and detriments are driven by the exact same species of fungi,” said Ost. “This is particularly true of Candida,” which is a “lifelong colonizer of intestinal microbiota that rarely causes disease but can be quite pathogenic when it does.”

A 2023 review in Nature Reviews Gastroenterology & Hepatology coauthored by Ost describes the role of commensal fungi in intestinal diseases, including IBD, colorectal cancer, and pancreatic cancer.

The pathogenic potential of commensal fungi is largely dependent on its strain, its morphology and its expression of virulence factors, researchers are learning. Ost has studied C albicans, which has been associated with intestinal inflammation and IBD. Like some other Candida species, C albicans are “fascinating shape shifters,” she said, transitioning between a less pathogenic “yeast” morphology and an elongated, adhesive “hyphae” shape that is more pathogenic.

It turns out, according to research by Ost and others, that the C albicans hyphal morphotype — and the adhesins (sticky proteins that facilitate adherence to epithelial cells) and a cytolytic toxin it produces — are preferentially targeted and suppressed by immunoglobulin A (IgA) in the gut.

“Our gut is protected by a large quantity of IgA antibodies…and these IgA interact with the microbiota and play a big role in what microbes are there and the biology of the microbes,” Ost said. Indeed, symptomatic IgA deficiency in humans has been shown to be associated with C albicans overgrowth.

Leveraging the hyphal-specific IgA response to protect against disease seems possible, she said, referring to an experimental anti-Candida fungal vaccine (NDV-3A) designed to induce an adhesin-specific immune response. In a mouse model of colitis, the vaccine protected against C albicans-associated damage. “We saw an immediate IgA response that targeted C albicans in the intestinal contents,” Ost said.

C glabrata, which has also been associated with intestinal inflammation and IBD, does not form hyphae but — depending on the strain — may also induce intestinal IgA responses, she said in describing her recent research.

Ost reported having no disclosures. Schooley disclosed being a consultant for SNIPR Biome, BiomX, Locus, MicrobiotiX, Amazon Data Monitoring Committee: Merck.

A version of this article appeared on Medscape.com.

WASHINGTON, DC — Age-related neurodegenerative disorders — motor neuron diseases, demyelinating diseases, Alzheimer’s disease, and other proteinopathies — are at an “inflection point,” said researcher Andrea R. Merchak, PhD, with a fuller understanding of disease pathophysiology but an overall dearth of effective disease-modifying treatments.

And this, Merchak said at the Gut Microbiota for Health (GMFH) World Summit 2025, is where the gut microbiome comes in. “The gut-brain axis is important to take into consideration,” she urged, both for gut microbiome researchers — whose collaboration with neurologists and neuroscientists is essential — and for practicing gastroenterologists.

“We are the sum of our environmental exposures,” said Merchak, assistant research professor of neurology at the Indiana University School of Medicine, in Indianapolis. “So for your patient populations, remember you’re not only treating the diseases they’re coming to you with, you’re also treating them for a lifetime of healthy [brain] aging.”

At the center of a healthy aging brain are the brain-residing microglia and peripheral monocytes, she said. These immune cell populations are directly influenced by blood-brain barrier breakdown, inflammation, and gut permeability — and indirectly influenced by microbial products, gastrointestinal (GI) function, and bacterial diversity, Merchak said at the meeting, which was convened by AGA and the European Society of Neurogastroenterology and Motility.

“Many of us grew up learning that the brain is an immune-privileged site, but we’ve been establishing that this is fundamentally not true,” she said. “While the brain does have a privileged status, there are interactions with the blood, with the peripheral immune cells.”

Merchak coauthored a 2024 review in Neurotherapeutics in which she and her colleagues explained that the brain is “heavily connected with peripheral immune dynamics,” and that the gut — as the largest immune organ in the body — is a critical place for peripheral immune development, “thus influencing brain health.”

Gut microbiota interact with the brain via several mechanisms including microbiota-derived metabolites that enter circulation, direct communication via the vagus nerve, and modulation of the immune system, Merchak and her coauthors wrote. Leaky gut, they noted, can lead to an accumulation of inflammatory signals and cells that can exacerbate or induce the onset of neurodegenerative conditions.

As researchers better understand the role that GI dysfunction plays in neurodegenerative disease — as they identify microbiome signatures for predicting risk, for instance — there will be “opportunities to target the microbiome to prevent or reverse dysbiosis as a way to delay, arrest or prevent the onset and progression of neurodegenerative diseases,” they wrote.

At the GMFH meeting, Merchak described both ongoing preclinical research that is dissecting gut-brain communication, and preliminary clinical evidence for the use of gut microbiota-modulating therapies in neurodegenerative disease.

 

Support for a Gut-Focused Approach

Research on bile acid metabolism in multiple sclerosis (MS) and on peripheral inflammation in dementia exemplify the ongoing preclinical research uncovering the mechanisms of gut-brain communication, Merchak said.

The finding that bile acid metabolism modulates MS autoimmunity comes from research done by Merchak and a team at the University of Virginia, Charlottesville, Virginia, several years ago in which mice with experimental autoimmune encephalomyelitis (EAE) — an animal model of MS — were engineered for T cell specific knockout of the aryl hydrocarbon receptor (AHR). The AHR has been directly tied to MS, and T lymphocytes are known to play a central role in MS pathophysiology.

Blocking the activity of AHR in CD4-positive T cells significantly affected the production of bile acids and other metabolites in the microbiome — and the outcome of central nervous system autoimmunity. “Mice with high levels of bile acids, both primary and secondary, actually recovered from this EAE” and regained motor function, Merchak said at the GMFH meeting.

The potential impact of genetic manipulation on recovery was ruled out — and the role of bile acids confirmed — when, using the EAE model, gut bacteria from mice without AHR were transplanted into mice with AHR. The mice with AHR were able to recover, confirming that AHR can reprogram the gut microbiome and that “high levels of bile acid can lead to reduced autoimmunity in an MS model,” she said.

Other elements and stages of the research, which was published in PLOS Biology in 2023, showed increased apoptosis of CD4-positive immune cells in AHR-deficient mice and the ability of oral taurocholic acid — a bile acid that was especially high in mice without AHR — to reduce the severity of EAE, Merchak said.

Evidence for the role of gut and peripheral inflammation on neurodegeneration is building on numerous fronts, Merchak said. Unpublished research using spatial transcriptomics of colon biopsies from patients with inflammatory bowel disease (IBD), patients with Parkinson’s disease (PD), and neurologically healthy control individuals, for instance, showed similar cell communication patterns in patients with IBD or PD (and no history of IBD) compared with healthy control individuals.

And in research using a single-cell genomics approach and a mouse model of lipopolysaccharide (LPS)-induced system neuroinflammation, microglia were found to preferentially communicate with peripheral myeloid cells rather than other microglia after peripheral LPS exposure.

“In saline-treated mice, the microglia are talking primarily to microglia, but in LPS-treated mice, microglia spend more time communicating with monocytes and T cells,” Merchak explained. “We see communication going from inside the brain to cells coming in from the periphery.”

In another experiment, 2 months of a high-fat, high-sugar diet in mice with an engineered predisposition to frontotemporal dementia led to significant upregulation of major histocompatibility complex class II (MHC II) expression on monocytes in the brain, she said, describing unpublished research. Because MHC II handles antigen presentation in the brain, the change signals increased central-peripheral immune crosstalk and increased brain inflammation.

 

State of Clinical Research

On the clinical side, Merchak said studies of gut microbiome-modulating therapies are currently not longitudinal enough to accurately study neurodegenerative diseases that may develop over decades. Still, her review of the literature — part of her 2024 article — suggests there is at least some preliminary clinical evidence for the use of probiotics/prebiotics/diet and fecal microbiota transplant (FMT) in several diseases.

• Parkinson’s Disease: “There has been some evidence,” Merchak said at the meeting, “for the treatment [with probiotics, prebiotics and diet] of nonmotor symptoms — things like gastrointestinal distress and mood changes — but no real evidence that such treatments can help with the motor symptoms we see in Parkinson’s.” Over 60 patients with PD have been treated with FMT, she said, with reduced GI distress and mixed results with motor symptoms.
• Alzheimer’s and related dementias: “Diet shows promise for cognitive outcomes, but there hasn’t been much evidence for probiotics,” she said. Her review found 17 patients diagnosed with dementia who were treated with FMT, “and for many of them, maintenance of cognitive function was reported — so no further decline — which is excellent.”
• Multiple Sclerosis: “We see higher quality-of-life measures in patients getting probiotics, prebiotics, and changes in diet,” Merchak said. “Again, most of this [relates to] mood and digestion, but some studies show a slowing of neurological damage as measured by MRI.” 

There are reports of 15 patients treated with FMT, and “three of these document full functional recovery,” she said, noting that longer follow-up is necessary as MS is characterized by relapsed and periods of recovery.

Merchak reported no financial disclosures.

A version of this article appeared on Medscape.com.

WASHINGTON, DC — Age-related neurodegenerative disorders — motor neuron diseases, demyelinating diseases, Alzheimer’s disease, and other proteinopathies — are at an “inflection point,” said researcher Andrea R. Merchak, PhD, with a fuller understanding of disease pathophysiology but an overall dearth of effective disease-modifying treatments.

And this, Merchak said at the Gut Microbiota for Health (GMFH) World Summit 2025, is where the gut microbiome comes in. “The gut-brain axis is important to take into consideration,” she urged, both for gut microbiome researchers — whose collaboration with neurologists and neuroscientists is essential — and for practicing gastroenterologists.

“We are the sum of our environmental exposures,” said Merchak, assistant research professor of neurology at the Indiana University School of Medicine, in Indianapolis. “So for your patient populations, remember you’re not only treating the diseases they’re coming to you with, you’re also treating them for a lifetime of healthy [brain] aging.”

At the center of a healthy aging brain are the brain-residing microglia and peripheral monocytes, she said. These immune cell populations are directly influenced by blood-brain barrier breakdown, inflammation, and gut permeability — and indirectly influenced by microbial products, gastrointestinal (GI) function, and bacterial diversity, Merchak said at the meeting, which was convened by AGA and the European Society of Neurogastroenterology and Motility.

“Many of us grew up learning that the brain is an immune-privileged site, but we’ve been establishing that this is fundamentally not true,” she said. “While the brain does have a privileged status, there are interactions with the blood, with the peripheral immune cells.”

Merchak coauthored a 2024 review in Neurotherapeutics in which she and her colleagues explained that the brain is “heavily connected with peripheral immune dynamics,” and that the gut — as the largest immune organ in the body — is a critical place for peripheral immune development, “thus influencing brain health.”

Gut microbiota interact with the brain via several mechanisms including microbiota-derived metabolites that enter circulation, direct communication via the vagus nerve, and modulation of the immune system, Merchak and her coauthors wrote. Leaky gut, they noted, can lead to an accumulation of inflammatory signals and cells that can exacerbate or induce the onset of neurodegenerative conditions.

As researchers better understand the role that GI dysfunction plays in neurodegenerative disease — as they identify microbiome signatures for predicting risk, for instance — there will be “opportunities to target the microbiome to prevent or reverse dysbiosis as a way to delay, arrest or prevent the onset and progression of neurodegenerative diseases,” they wrote.

At the GMFH meeting, Merchak described both ongoing preclinical research that is dissecting gut-brain communication, and preliminary clinical evidence for the use of gut microbiota-modulating therapies in neurodegenerative disease.

 

Support for a Gut-Focused Approach

Research on bile acid metabolism in multiple sclerosis (MS) and on peripheral inflammation in dementia exemplify the ongoing preclinical research uncovering the mechanisms of gut-brain communication, Merchak said.

The finding that bile acid metabolism modulates MS autoimmunity comes from research done by Merchak and a team at the University of Virginia, Charlottesville, Virginia, several years ago in which mice with experimental autoimmune encephalomyelitis (EAE) — an animal model of MS — were engineered for T cell specific knockout of the aryl hydrocarbon receptor (AHR). The AHR has been directly tied to MS, and T lymphocytes are known to play a central role in MS pathophysiology.

Blocking the activity of AHR in CD4-positive T cells significantly affected the production of bile acids and other metabolites in the microbiome — and the outcome of central nervous system autoimmunity. “Mice with high levels of bile acids, both primary and secondary, actually recovered from this EAE” and regained motor function, Merchak said at the GMFH meeting.

The potential impact of genetic manipulation on recovery was ruled out — and the role of bile acids confirmed — when, using the EAE model, gut bacteria from mice without AHR were transplanted into mice with AHR. The mice with AHR were able to recover, confirming that AHR can reprogram the gut microbiome and that “high levels of bile acid can lead to reduced autoimmunity in an MS model,” she said.

Other elements and stages of the research, which was published in PLOS Biology in 2023, showed increased apoptosis of CD4-positive immune cells in AHR-deficient mice and the ability of oral taurocholic acid — a bile acid that was especially high in mice without AHR — to reduce the severity of EAE, Merchak said.

Evidence for the role of gut and peripheral inflammation on neurodegeneration is building on numerous fronts, Merchak said. Unpublished research using spatial transcriptomics of colon biopsies from patients with inflammatory bowel disease (IBD), patients with Parkinson’s disease (PD), and neurologically healthy control individuals, for instance, showed similar cell communication patterns in patients with IBD or PD (and no history of IBD) compared with healthy control individuals.

And in research using a single-cell genomics approach and a mouse model of lipopolysaccharide (LPS)-induced system neuroinflammation, microglia were found to preferentially communicate with peripheral myeloid cells rather than other microglia after peripheral LPS exposure.

“In saline-treated mice, the microglia are talking primarily to microglia, but in LPS-treated mice, microglia spend more time communicating with monocytes and T cells,” Merchak explained. “We see communication going from inside the brain to cells coming in from the periphery.”

In another experiment, 2 months of a high-fat, high-sugar diet in mice with an engineered predisposition to frontotemporal dementia led to significant upregulation of major histocompatibility complex class II (MHC II) expression on monocytes in the brain, she said, describing unpublished research. Because MHC II handles antigen presentation in the brain, the change signals increased central-peripheral immune crosstalk and increased brain inflammation.

 

State of Clinical Research

On the clinical side, Merchak said studies of gut microbiome-modulating therapies are currently not longitudinal enough to accurately study neurodegenerative diseases that may develop over decades. Still, her review of the literature — part of her 2024 article — suggests there is at least some preliminary clinical evidence for the use of probiotics/prebiotics/diet and fecal microbiota transplant (FMT) in several diseases.

• Parkinson’s Disease: “There has been some evidence,” Merchak said at the meeting, “for the treatment [with probiotics, prebiotics and diet] of nonmotor symptoms — things like gastrointestinal distress and mood changes — but no real evidence that such treatments can help with the motor symptoms we see in Parkinson’s.” Over 60 patients with PD have been treated with FMT, she said, with reduced GI distress and mixed results with motor symptoms.
• Alzheimer’s and related dementias: “Diet shows promise for cognitive outcomes, but there hasn’t been much evidence for probiotics,” she said. Her review found 17 patients diagnosed with dementia who were treated with FMT, “and for many of them, maintenance of cognitive function was reported — so no further decline — which is excellent.”
• Multiple Sclerosis: “We see higher quality-of-life measures in patients getting probiotics, prebiotics, and changes in diet,” Merchak said. “Again, most of this [relates to] mood and digestion, but some studies show a slowing of neurological damage as measured by MRI.” 

There are reports of 15 patients treated with FMT, and “three of these document full functional recovery,” she said, noting that longer follow-up is necessary as MS is characterized by relapsed and periods of recovery.

Merchak reported no financial disclosures.

A version of this article appeared on Medscape.com.

WASHINGTON, DC — Age-related neurodegenerative disorders — motor neuron diseases, demyelinating diseases, Alzheimer’s disease, and other proteinopathies — are at an “inflection point,” said researcher Andrea R. Merchak, PhD, with a fuller understanding of disease pathophysiology but an overall dearth of effective disease-modifying treatments.

And this, Merchak said at the Gut Microbiota for Health (GMFH) World Summit 2025, is where the gut microbiome comes in. “The gut-brain axis is important to take into consideration,” she urged, both for gut microbiome researchers — whose collaboration with neurologists and neuroscientists is essential — and for practicing gastroenterologists.

“We are the sum of our environmental exposures,” said Merchak, assistant research professor of neurology at the Indiana University School of Medicine, in Indianapolis. “So for your patient populations, remember you’re not only treating the diseases they’re coming to you with, you’re also treating them for a lifetime of healthy [brain] aging.”

At the center of a healthy aging brain are the brain-residing microglia and peripheral monocytes, she said. These immune cell populations are directly influenced by blood-brain barrier breakdown, inflammation, and gut permeability — and indirectly influenced by microbial products, gastrointestinal (GI) function, and bacterial diversity, Merchak said at the meeting, which was convened by AGA and the European Society of Neurogastroenterology and Motility.

“Many of us grew up learning that the brain is an immune-privileged site, but we’ve been establishing that this is fundamentally not true,” she said. “While the brain does have a privileged status, there are interactions with the blood, with the peripheral immune cells.”

Merchak coauthored a 2024 review in Neurotherapeutics in which she and her colleagues explained that the brain is “heavily connected with peripheral immune dynamics,” and that the gut — as the largest immune organ in the body — is a critical place for peripheral immune development, “thus influencing brain health.”

Gut microbiota interact with the brain via several mechanisms including microbiota-derived metabolites that enter circulation, direct communication via the vagus nerve, and modulation of the immune system, Merchak and her coauthors wrote. Leaky gut, they noted, can lead to an accumulation of inflammatory signals and cells that can exacerbate or induce the onset of neurodegenerative conditions.

As researchers better understand the role that GI dysfunction plays in neurodegenerative disease — as they identify microbiome signatures for predicting risk, for instance — there will be “opportunities to target the microbiome to prevent or reverse dysbiosis as a way to delay, arrest or prevent the onset and progression of neurodegenerative diseases,” they wrote.

At the GMFH meeting, Merchak described both ongoing preclinical research that is dissecting gut-brain communication, and preliminary clinical evidence for the use of gut microbiota-modulating therapies in neurodegenerative disease.

 

Support for a Gut-Focused Approach

Research on bile acid metabolism in multiple sclerosis (MS) and on peripheral inflammation in dementia exemplify the ongoing preclinical research uncovering the mechanisms of gut-brain communication, Merchak said.

The finding that bile acid metabolism modulates MS autoimmunity comes from research done by Merchak and a team at the University of Virginia, Charlottesville, Virginia, several years ago in which mice with experimental autoimmune encephalomyelitis (EAE) — an animal model of MS — were engineered for T cell specific knockout of the aryl hydrocarbon receptor (AHR). The AHR has been directly tied to MS, and T lymphocytes are known to play a central role in MS pathophysiology.

Blocking the activity of AHR in CD4-positive T cells significantly affected the production of bile acids and other metabolites in the microbiome — and the outcome of central nervous system autoimmunity. “Mice with high levels of bile acids, both primary and secondary, actually recovered from this EAE” and regained motor function, Merchak said at the GMFH meeting.

The potential impact of genetic manipulation on recovery was ruled out — and the role of bile acids confirmed — when, using the EAE model, gut bacteria from mice without AHR were transplanted into mice with AHR. The mice with AHR were able to recover, confirming that AHR can reprogram the gut microbiome and that “high levels of bile acid can lead to reduced autoimmunity in an MS model,” she said.

Other elements and stages of the research, which was published in PLOS Biology in 2023, showed increased apoptosis of CD4-positive immune cells in AHR-deficient mice and the ability of oral taurocholic acid — a bile acid that was especially high in mice without AHR — to reduce the severity of EAE, Merchak said.

Evidence for the role of gut and peripheral inflammation on neurodegeneration is building on numerous fronts, Merchak said. Unpublished research using spatial transcriptomics of colon biopsies from patients with inflammatory bowel disease (IBD), patients with Parkinson’s disease (PD), and neurologically healthy control individuals, for instance, showed similar cell communication patterns in patients with IBD or PD (and no history of IBD) compared with healthy control individuals.

And in research using a single-cell genomics approach and a mouse model of lipopolysaccharide (LPS)-induced system neuroinflammation, microglia were found to preferentially communicate with peripheral myeloid cells rather than other microglia after peripheral LPS exposure.

“In saline-treated mice, the microglia are talking primarily to microglia, but in LPS-treated mice, microglia spend more time communicating with monocytes and T cells,” Merchak explained. “We see communication going from inside the brain to cells coming in from the periphery.”

In another experiment, 2 months of a high-fat, high-sugar diet in mice with an engineered predisposition to frontotemporal dementia led to significant upregulation of major histocompatibility complex class II (MHC II) expression on monocytes in the brain, she said, describing unpublished research. Because MHC II handles antigen presentation in the brain, the change signals increased central-peripheral immune crosstalk and increased brain inflammation.

 

State of Clinical Research

On the clinical side, Merchak said studies of gut microbiome-modulating therapies are currently not longitudinal enough to accurately study neurodegenerative diseases that may develop over decades. Still, her review of the literature — part of her 2024 article — suggests there is at least some preliminary clinical evidence for the use of probiotics/prebiotics/diet and fecal microbiota transplant (FMT) in several diseases.

• Parkinson’s Disease: “There has been some evidence,” Merchak said at the meeting, “for the treatment [with probiotics, prebiotics and diet] of nonmotor symptoms — things like gastrointestinal distress and mood changes — but no real evidence that such treatments can help with the motor symptoms we see in Parkinson’s.” Over 60 patients with PD have been treated with FMT, she said, with reduced GI distress and mixed results with motor symptoms.
• Alzheimer’s and related dementias: “Diet shows promise for cognitive outcomes, but there hasn’t been much evidence for probiotics,” she said. Her review found 17 patients diagnosed with dementia who were treated with FMT, “and for many of them, maintenance of cognitive function was reported — so no further decline — which is excellent.”
• Multiple Sclerosis: “We see higher quality-of-life measures in patients getting probiotics, prebiotics, and changes in diet,” Merchak said. “Again, most of this [relates to] mood and digestion, but some studies show a slowing of neurological damage as measured by MRI.” 

There are reports of 15 patients treated with FMT, and “three of these document full functional recovery,” she said, noting that longer follow-up is necessary as MS is characterized by relapsed and periods of recovery.

Merchak reported no financial disclosures.

A version of this article appeared on Medscape.com.

BERLIN — Ulcerative colitis (UC) patients who fail on first-line therapy appear to have better outcomes with vedolizumab (Entyvio) than with infliximab, suggests EFFICACI, the first trial directly comparing second-line advanced therapies in patients with the disease.

Vedolizumab was superior to infliximab to achieving steroid-free clinical remission at week 14 in patients who had failed on a first-line subcutaneous anti–tumor necrosis factor (anti-TNF) therapy, said study presenter Guillaume Bouguen, MD, PhD, of the gastroenterology gepartment, CHU Rennes – Pontchaillou Hospital, France.

The drug also outperformed infliximab in the induction of endoscopic improvement, and its safety outcomes were “consistent with the known profile of both drugs in previous trials,” Bouguen said.

The research was presented at the European Crohn’s and Colitis Organisation 2025 Congress.

 

The study reports only short-term outcomes, so it “remains unclear whether vedolizumab’s advantage is sustained over time or whether infliximab may catch up in effectiveness,” Tauseef Ali, MD, AGAF, executive medical director, SSM Health St. Anthony Digestive Care, Crohn’s and Colitis Center, Oklahoma City, said in an interview.

Bouguen noted that the trial was unblinded at week 14 and that patients were followed up to week 54, data for which will be presented in the near future.

 

Head-to-Head Trial

Treating ulcerative colitis beyond the first line of therapy is “becoming challenging” because there are several therapeutic classes and drugs to choose from but no strong evidence to support physician decision-making, Bouguen said.

No head-to-head trials for second-line advanced therapies for UC had been performed, he said. So Bouguen and colleagues conducted a randomized, double-blind trial to determine whether vedolizumab, an integrin receptor agonist, is superior to infliximab, a TNF antagonist, in ulcerative colitis patients who had failed a first-line subcutaneous TNF antagonist.

They enrolled patients with moderate to severe disease, defined by a total Mayo score ≥ 6, despite at least 12 weeks of treatment with the TNF antagonists golimumab (Simponi) or adalimumab (Humira and others), from 24 centers across France.

Participants were randomly assigned to intravenous 300 mg vedolizumab or 5 mg/kg infliximab. Clinical biological assessments performed at baseline and at weeks 2 and 6. The primary endpoint was steroid-free clinical remission (Mayo score ≤ 2) at week 14.

Of 165 patients assessed for eligibility, 78 were randomly assigned to vedolizumab and 73 to infliximab, of whom 77 and 70 and patients, respectively, were available for assessment at week 14. Approximately 40% of the participants were women, and the average age was almost 40 years.

The mean total Mayo score at baseline was comparable between the two groups (9.0 vedolizumab; 8.7 infliximab). The majority in both groups had previously been treated with adalimumab, and almost 60% had experienced a loss of response to therapy.

Steroid-free clinical remission at week 14 was achieved by 34.6% of patients treated with vedolizumab vs 19.2% of those given infliximab (P = .033).

Endoscopic remission at week 14 was achieved by 19.5% of patients in the vedolizumab group vs 8.3% of those treated with infliximab (P = .0507), while endoscopic improvement was seen in 46.8% and 29.2% of patients, respectively (P = .0273).

There were no statistically significant differences between the two treatment groups in rates of clinical response or mean C-reactive protein (CRP) levels between baseline and week 14, and there was no significant difference in fecal calprotectin levels at week 14.

Interestingly, Bouguen said that, from parameters such as age, sex, Mayo score, CRP levels, and concomitant immunosuppressant use, there were no significant predictors of clinical remission.

The overall incidence of adverse events, including respiratory tract and Clostridioides difficile infections, was comparable between the vedolizumab and infliximab groups, although patients receiving infliximab had higher rates of disease worsening and infusion reactions.

 

Questions Remain

Study coinvestigator Matthieu Allez, MD, PhD, head of the gastroenterology department, Hôpital Saint-Louis, Assistance Publique Hopitaux de Paris, said in an interview that he was surprised by the findings.

“I think infliximab is a much better drug than vedolizumab,” considering the rate of immunosuppressant combination therapy that is administered in ulcerative colitis, said Allez, who was the session’s co-chair.

This is a “key aspect” as “you can give more” of such therapy to patients receiving infliximab, “but, in fact, it seems like they do better” with vedolizumab, Allez said.

Ali said that the trial “addresses a critical gap in the treatment of ulcerative colitis: Whether switching within the anti-TNF class or swapping to vedolizumab is more effective after failure of a first subcutaneous anti-TNF.”

“This question has real-world clinical relevance, as gastroenterologists often face this decision,” he added.

Ali, who was not involved in the study, said that even though the results “suggest that vedolizumab may be a more effective option than infliximab in this patient population” and there were no major safety concerns with either drug, “one must exercise caution in interpreting and applying the results to clinical practice.”

Moreover, the lack of statistically significant clinical response rates between the drugs “raises questions about whether the primary endpoint difference is clinically meaningful over the long term,” he said.

The study was conducted in only one country, thus potentially limiting its generalizability, Ali noted, and it included only patients who had failed on subcutaneous, not intravenous, anti-TNF therapy. There was also a lack of biomarker stratification, “making it unclear which patients would benefit most from switching vs swapping strategies,” he added.

“While vedolizumab may be preferable, many other factors,” such as drug serum levels, immunogenicity, urgency of response, access, and cost, “should guide decision-making,” Ali said.

The study was funded by the French national research program, with additional funding from Takeda. Bouguen declared relationships with Abbvie, Janssen, Lilly, Takeda, Celltrion, Sandoz, Galapagos, Tillotts, and Amgen. No other disclosures were reported.

A version of this article appeared on Medscape.com.

BERLIN — Ulcerative colitis (UC) patients who fail on first-line therapy appear to have better outcomes with vedolizumab (Entyvio) than with infliximab, suggests EFFICACI, the first trial directly comparing second-line advanced therapies in patients with the disease.

Vedolizumab was superior to infliximab to achieving steroid-free clinical remission at week 14 in patients who had failed on a first-line subcutaneous anti–tumor necrosis factor (anti-TNF) therapy, said study presenter Guillaume Bouguen, MD, PhD, of the gastroenterology gepartment, CHU Rennes – Pontchaillou Hospital, France.

The drug also outperformed infliximab in the induction of endoscopic improvement, and its safety outcomes were “consistent with the known profile of both drugs in previous trials,” Bouguen said.

The research was presented at the European Crohn’s and Colitis Organisation 2025 Congress.

 

The study reports only short-term outcomes, so it “remains unclear whether vedolizumab’s advantage is sustained over time or whether infliximab may catch up in effectiveness,” Tauseef Ali, MD, AGAF, executive medical director, SSM Health St. Anthony Digestive Care, Crohn’s and Colitis Center, Oklahoma City, said in an interview.

Bouguen noted that the trial was unblinded at week 14 and that patients were followed up to week 54, data for which will be presented in the near future.

 

Head-to-Head Trial

Treating ulcerative colitis beyond the first line of therapy is “becoming challenging” because there are several therapeutic classes and drugs to choose from but no strong evidence to support physician decision-making, Bouguen said.

No head-to-head trials for second-line advanced therapies for UC had been performed, he said. So Bouguen and colleagues conducted a randomized, double-blind trial to determine whether vedolizumab, an integrin receptor agonist, is superior to infliximab, a TNF antagonist, in ulcerative colitis patients who had failed a first-line subcutaneous TNF antagonist.

They enrolled patients with moderate to severe disease, defined by a total Mayo score ≥ 6, despite at least 12 weeks of treatment with the TNF antagonists golimumab (Simponi) or adalimumab (Humira and others), from 24 centers across France.

Participants were randomly assigned to intravenous 300 mg vedolizumab or 5 mg/kg infliximab. Clinical biological assessments performed at baseline and at weeks 2 and 6. The primary endpoint was steroid-free clinical remission (Mayo score ≤ 2) at week 14.

Of 165 patients assessed for eligibility, 78 were randomly assigned to vedolizumab and 73 to infliximab, of whom 77 and 70 and patients, respectively, were available for assessment at week 14. Approximately 40% of the participants were women, and the average age was almost 40 years.

The mean total Mayo score at baseline was comparable between the two groups (9.0 vedolizumab; 8.7 infliximab). The majority in both groups had previously been treated with adalimumab, and almost 60% had experienced a loss of response to therapy.

Steroid-free clinical remission at week 14 was achieved by 34.6% of patients treated with vedolizumab vs 19.2% of those given infliximab (P = .033).

Endoscopic remission at week 14 was achieved by 19.5% of patients in the vedolizumab group vs 8.3% of those treated with infliximab (P = .0507), while endoscopic improvement was seen in 46.8% and 29.2% of patients, respectively (P = .0273).

There were no statistically significant differences between the two treatment groups in rates of clinical response or mean C-reactive protein (CRP) levels between baseline and week 14, and there was no significant difference in fecal calprotectin levels at week 14.

Interestingly, Bouguen said that, from parameters such as age, sex, Mayo score, CRP levels, and concomitant immunosuppressant use, there were no significant predictors of clinical remission.

The overall incidence of adverse events, including respiratory tract and Clostridioides difficile infections, was comparable between the vedolizumab and infliximab groups, although patients receiving infliximab had higher rates of disease worsening and infusion reactions.

 

Questions Remain

Study coinvestigator Matthieu Allez, MD, PhD, head of the gastroenterology department, Hôpital Saint-Louis, Assistance Publique Hopitaux de Paris, said in an interview that he was surprised by the findings.

“I think infliximab is a much better drug than vedolizumab,” considering the rate of immunosuppressant combination therapy that is administered in ulcerative colitis, said Allez, who was the session’s co-chair.

This is a “key aspect” as “you can give more” of such therapy to patients receiving infliximab, “but, in fact, it seems like they do better” with vedolizumab, Allez said.

Ali said that the trial “addresses a critical gap in the treatment of ulcerative colitis: Whether switching within the anti-TNF class or swapping to vedolizumab is more effective after failure of a first subcutaneous anti-TNF.”

“This question has real-world clinical relevance, as gastroenterologists often face this decision,” he added.

Ali, who was not involved in the study, said that even though the results “suggest that vedolizumab may be a more effective option than infliximab in this patient population” and there were no major safety concerns with either drug, “one must exercise caution in interpreting and applying the results to clinical practice.”

Moreover, the lack of statistically significant clinical response rates between the drugs “raises questions about whether the primary endpoint difference is clinically meaningful over the long term,” he said.

The study was conducted in only one country, thus potentially limiting its generalizability, Ali noted, and it included only patients who had failed on subcutaneous, not intravenous, anti-TNF therapy. There was also a lack of biomarker stratification, “making it unclear which patients would benefit most from switching vs swapping strategies,” he added.

“While vedolizumab may be preferable, many other factors,” such as drug serum levels, immunogenicity, urgency of response, access, and cost, “should guide decision-making,” Ali said.

The study was funded by the French national research program, with additional funding from Takeda. Bouguen declared relationships with Abbvie, Janssen, Lilly, Takeda, Celltrion, Sandoz, Galapagos, Tillotts, and Amgen. No other disclosures were reported.

A version of this article appeared on Medscape.com.

BERLIN — Ulcerative colitis (UC) patients who fail on first-line therapy appear to have better outcomes with vedolizumab (Entyvio) than with infliximab, suggests EFFICACI, the first trial directly comparing second-line advanced therapies in patients with the disease.

Vedolizumab was superior to infliximab to achieving steroid-free clinical remission at week 14 in patients who had failed on a first-line subcutaneous anti–tumor necrosis factor (anti-TNF) therapy, said study presenter Guillaume Bouguen, MD, PhD, of the gastroenterology gepartment, CHU Rennes – Pontchaillou Hospital, France.

The drug also outperformed infliximab in the induction of endoscopic improvement, and its safety outcomes were “consistent with the known profile of both drugs in previous trials,” Bouguen said.

The research was presented at the European Crohn’s and Colitis Organisation 2025 Congress.

 

The study reports only short-term outcomes, so it “remains unclear whether vedolizumab’s advantage is sustained over time or whether infliximab may catch up in effectiveness,” Tauseef Ali, MD, AGAF, executive medical director, SSM Health St. Anthony Digestive Care, Crohn’s and Colitis Center, Oklahoma City, said in an interview.

Bouguen noted that the trial was unblinded at week 14 and that patients were followed up to week 54, data for which will be presented in the near future.

 

Head-to-Head Trial

Treating ulcerative colitis beyond the first line of therapy is “becoming challenging” because there are several therapeutic classes and drugs to choose from but no strong evidence to support physician decision-making, Bouguen said.

No head-to-head trials for second-line advanced therapies for UC had been performed, he said. So Bouguen and colleagues conducted a randomized, double-blind trial to determine whether vedolizumab, an integrin receptor agonist, is superior to infliximab, a TNF antagonist, in ulcerative colitis patients who had failed a first-line subcutaneous TNF antagonist.

They enrolled patients with moderate to severe disease, defined by a total Mayo score ≥ 6, despite at least 12 weeks of treatment with the TNF antagonists golimumab (Simponi) or adalimumab (Humira and others), from 24 centers across France.

Participants were randomly assigned to intravenous 300 mg vedolizumab or 5 mg/kg infliximab. Clinical biological assessments performed at baseline and at weeks 2 and 6. The primary endpoint was steroid-free clinical remission (Mayo score ≤ 2) at week 14.

Of 165 patients assessed for eligibility, 78 were randomly assigned to vedolizumab and 73 to infliximab, of whom 77 and 70 and patients, respectively, were available for assessment at week 14. Approximately 40% of the participants were women, and the average age was almost 40 years.

The mean total Mayo score at baseline was comparable between the two groups (9.0 vedolizumab; 8.7 infliximab). The majority in both groups had previously been treated with adalimumab, and almost 60% had experienced a loss of response to therapy.

Steroid-free clinical remission at week 14 was achieved by 34.6% of patients treated with vedolizumab vs 19.2% of those given infliximab (P = .033).

Endoscopic remission at week 14 was achieved by 19.5% of patients in the vedolizumab group vs 8.3% of those treated with infliximab (P = .0507), while endoscopic improvement was seen in 46.8% and 29.2% of patients, respectively (P = .0273).

There were no statistically significant differences between the two treatment groups in rates of clinical response or mean C-reactive protein (CRP) levels between baseline and week 14, and there was no significant difference in fecal calprotectin levels at week 14.

Interestingly, Bouguen said that, from parameters such as age, sex, Mayo score, CRP levels, and concomitant immunosuppressant use, there were no significant predictors of clinical remission.

The overall incidence of adverse events, including respiratory tract and Clostridioides difficile infections, was comparable between the vedolizumab and infliximab groups, although patients receiving infliximab had higher rates of disease worsening and infusion reactions.

 

Questions Remain

Study coinvestigator Matthieu Allez, MD, PhD, head of the gastroenterology department, Hôpital Saint-Louis, Assistance Publique Hopitaux de Paris, said in an interview that he was surprised by the findings.

“I think infliximab is a much better drug than vedolizumab,” considering the rate of immunosuppressant combination therapy that is administered in ulcerative colitis, said Allez, who was the session’s co-chair.

This is a “key aspect” as “you can give more” of such therapy to patients receiving infliximab, “but, in fact, it seems like they do better” with vedolizumab, Allez said.

Ali said that the trial “addresses a critical gap in the treatment of ulcerative colitis: Whether switching within the anti-TNF class or swapping to vedolizumab is more effective after failure of a first subcutaneous anti-TNF.”

“This question has real-world clinical relevance, as gastroenterologists often face this decision,” he added.

Ali, who was not involved in the study, said that even though the results “suggest that vedolizumab may be a more effective option than infliximab in this patient population” and there were no major safety concerns with either drug, “one must exercise caution in interpreting and applying the results to clinical practice.”

Moreover, the lack of statistically significant clinical response rates between the drugs “raises questions about whether the primary endpoint difference is clinically meaningful over the long term,” he said.

The study was conducted in only one country, thus potentially limiting its generalizability, Ali noted, and it included only patients who had failed on subcutaneous, not intravenous, anti-TNF therapy. There was also a lack of biomarker stratification, “making it unclear which patients would benefit most from switching vs swapping strategies,” he added.

“While vedolizumab may be preferable, many other factors,” such as drug serum levels, immunogenicity, urgency of response, access, and cost, “should guide decision-making,” Ali said.

The study was funded by the French national research program, with additional funding from Takeda. Bouguen declared relationships with Abbvie, Janssen, Lilly, Takeda, Celltrion, Sandoz, Galapagos, Tillotts, and Amgen. No other disclosures were reported.

A version of this article appeared on Medscape.com.

BERLIN — Induction therapy with subcutaneous guselkumab demonstrated significant efficacy in patients with moderately to severely active ulcerative colitis (UC), according to results from the phase 3, randomized, double-blind, placebo-controlled ASTRO study.

Importantly, the study also showed that subcutaneous induction is consistent with intravenous (IV) induction of guselkumab in UC.

“The flexibility of a fully subcutaneous treatment regimen would be a welcome option for many patients, especially those with busy and active lifestyles,” said study lead Laurent Peyrin-Biroulet, MD, head of the inflammatory bowel disease (IBD) unit at University Hospital of Nancy, France.

Peyrin-Biroulet presented the results at European Crohn’s and Colitis Organisation (ECCO) 2025 Congress.

“I think it’s an evolution and improvement in terms of IBD management,” he said. “We are happy that our patients will have the choice.”

Guselkumab is a selective dual-acting interleukin (IL)–23p19 subunit inhibitor that potently blocks IL-23 and binds to CD64, a receptor on cells that produce IL-23, and is the only full subcutaneous IL-23 available. The drug is approved in some countries, including the United States, for UC.

 

The ASTRO Study

Building on data from the QUASAR studies, which showed the efficacy of induction of IV guselkumab and subcutaneous maintenance in patients with UC, the ASTRO study randomly assigned 418 patients with moderately to severely active UC to receive either induction with 400 mg subcutaneous guselkumab at weeks 0, 4, and 8 or placebo.

After induction, the treatment group either received a maintenance dose of 200 mg subcutaneous guselkumab at week 12 and then every 4 weeks or 100 mg every 8 weeks (starting week 16).

All patients had an inadequate response or intolerance to conventional therapy. Around 60% were naive to biologics, Janus kinase (JAK) inhibitors, or sphingosine-1-phosphate receptor modulators (S1Ps).

Clinical remission at week 12 — the primary endpoint — was achieved by 27.6% of all patients treated with guselkumab compared with 6.5% of patients on placebo (P < .001).

“These results are in line with the QUASAR data,” in which clinical remission was 22.6% with IV guselkumab at 12 weeks, noted Peyrin-Biroulet.

The researchers also divided the results by prespecified subgroups based on previous treatments.

Clinical remission was achieved at week 12 by 36% of patients naive to biologics, JAK inhibitors, or S1Ps in the guselkumab group and by 8.9% of these patients in the placebo group (P < .001). Among patients who had previously received biologics, JAK inhibitors, or S1Ps, 16.1% of those in the guselkumab group achieved clinical remission compared with 3.6% of those in the placebo group (P = .005).

“In terms of symptomatic remission at week 12, the difference between the overall guselkumab result and placebo was 30%,” reported Peyrin-Biroulet.

Clinical response — defined as a decrease in the modified Mayo score by ≥ 30% and ≥ 2 points, with either a ≥ 1-point decrease from baseline in the rectal bleeding subscore or a rectal bleeding subscore of 0 or 1 — was 65.6% in the guselkumab group compared with 34.5% in the placebo group (P < .001).

Among patients naive to biologics, JAK inhibitors, or S1Ps, clinical response was 71.3% in the guselkumab group, compared with 41.8% in the placebo group (P < .001). Among those who had previously received biologics, JAK inhibitors, or S1Ps, it was 57.1% in the guselkumab group, compared with 25.0% in the placebo group (P < .001).

Turning to endoscopic improvement (ie, an endoscopic subscore of 0 or 1 with no friability), 37.3% of those in the guselkumab group overall, compared with 12.9% of those in the placebo group who achieved this endpoint (P < .001).

“This is a treatment effect of over 20%,” said Peyrin-Biroulet. “We know that when it is over 20%, it is considered game changer.”

In patients naive to biologics, JAK inhibitors, or S1Ps, endoscopic improvement was 45.7% with guselkumab vs 17.7% with placebo. In those who had previously received biologics, JAK inhibitors, or S1Ps, endoscopic improvement was 24.1% with guselkumab vs 7.1% with placebo. Both were statistically significant.

The safety of subcutaneous induction therapy was consistent with the well-characterized and favorable safety profile of guselkumab in approved indications.

 

The GRAVITI Study

In the phase 3, randomized, double-blind, placebo-controlled GRAVITI study, also presented at ECCO 2025 Congress, researchers evaluated the efficacy and safety of induction with subcutaneous guselkumab followed by subcutaneous maintenance compared with placebo in patients with moderately to severely active Crohn’s disease.

The GRAVITI study followed the same induction and maintenance dosage and treatment intervals as the ASTRO study.

In addition, the patients randomly assigned to placebo were able to receive subcutaneous guselkumab (400 mg every 4 weeks followed by 100 mg every 8 weeks) if rescue criteria were met at week 16.

The co-primary endpoints were clinical remission and endoscopic response at week 12.

Ailsa Hart, MD, director, IBD Research, and consultant gastroenterologist, St. Mark’s Hospital and Imperial College, both in London, reported the 12-week and 48-week results, which were initially presented at the American College of Gastroenterology (ACG) meeting in October 2024.

At week 12, 56.1% of patients who received guselkumab achieved clinical remission, compared with 21.4% of patients who received placebo. Endoscopic response was achieved in 41.3% of patients treated with guselkumab compared with 21.4% in the placebo group.

Regarding the 48-week results, Hart noted that the rate of clinical remission was more than three times higher with both maintenance doses of guselkumab at 66.1% (200 mg) and 60.0% (100 mg) vs 17.1% with placebo.

Endoscopic response at 48 weeks was achieved in 51.3% of patients on the 200-mg maintenance dose and in 44.3% on the 100-mg maintenance dose, compared with 6.8% of patients on placebo.

In addition, endoscopic remission was achieved in 38.3% of patients in the 200-mg guselkumab group and in 30.4% in the 100-mg guselkumab group, compared with 6.0% in the placebo group.

Safety findings were consistent with the known safety profile of guselkumab in approved indications and other studies in IBD.

“These results complement the GALAXI data and demonstrate that both IV and subcutaneous guselkumab induction are efficacious and therapeutic in Crohn’s disease,” Hart said. Furthermore, data from the ASTRO study demonstrated similar data in the UC population.

As clinicians, this gives us flexibility in how we treat our patients; although, the rationale for choosing subcutaneous or IV is likely to be pragmatic, Hart said.

Additionally, the flexibility of the maintenance therapy, that is, 200 mg subcutaneous guselkumab every 4 weeks or 100 mg every 8 weeks, “is expected to positively affect several parameters of therapy, including increased compliance, hospital avoidance, and better safety profiling,” comoderator Giorgos Bamias, MD, professor of gastroenterology at the School of Medicine, National and Kapodistrian University of Athens, said in an interview.

It appears that multiple options will be offered to patients regarding treatment with guselkumab for patients with Crohn’s disease, Bamias said. “Interestingly, a similar multiplicity of options has also been shown for ulcerative colitis, through the QUASAR and ASTRO studies.”

Peyrin-Biroulet declared receiving grants and other/support travel from multiple companies. Hart declared receiving grants and personal fees from multiple companies. Bamias declared receiving grants and personal fees/honoraria as an advisor/lecturer from multiple companies.

A version of this article appeared on Medscape.com.

BERLIN — Induction therapy with subcutaneous guselkumab demonstrated significant efficacy in patients with moderately to severely active ulcerative colitis (UC), according to results from the phase 3, randomized, double-blind, placebo-controlled ASTRO study.

Importantly, the study also showed that subcutaneous induction is consistent with intravenous (IV) induction of guselkumab in UC.

“The flexibility of a fully subcutaneous treatment regimen would be a welcome option for many patients, especially those with busy and active lifestyles,” said study lead Laurent Peyrin-Biroulet, MD, head of the inflammatory bowel disease (IBD) unit at University Hospital of Nancy, France.

Peyrin-Biroulet presented the results at European Crohn’s and Colitis Organisation (ECCO) 2025 Congress.

“I think it’s an evolution and improvement in terms of IBD management,” he said. “We are happy that our patients will have the choice.”

Guselkumab is a selective dual-acting interleukin (IL)–23p19 subunit inhibitor that potently blocks IL-23 and binds to CD64, a receptor on cells that produce IL-23, and is the only full subcutaneous IL-23 available. The drug is approved in some countries, including the United States, for UC.

 

The ASTRO Study

Building on data from the QUASAR studies, which showed the efficacy of induction of IV guselkumab and subcutaneous maintenance in patients with UC, the ASTRO study randomly assigned 418 patients with moderately to severely active UC to receive either induction with 400 mg subcutaneous guselkumab at weeks 0, 4, and 8 or placebo.

After induction, the treatment group either received a maintenance dose of 200 mg subcutaneous guselkumab at week 12 and then every 4 weeks or 100 mg every 8 weeks (starting week 16).

All patients had an inadequate response or intolerance to conventional therapy. Around 60% were naive to biologics, Janus kinase (JAK) inhibitors, or sphingosine-1-phosphate receptor modulators (S1Ps).

Clinical remission at week 12 — the primary endpoint — was achieved by 27.6% of all patients treated with guselkumab compared with 6.5% of patients on placebo (P < .001).

“These results are in line with the QUASAR data,” in which clinical remission was 22.6% with IV guselkumab at 12 weeks, noted Peyrin-Biroulet.

The researchers also divided the results by prespecified subgroups based on previous treatments.

Clinical remission was achieved at week 12 by 36% of patients naive to biologics, JAK inhibitors, or S1Ps in the guselkumab group and by 8.9% of these patients in the placebo group (P < .001). Among patients who had previously received biologics, JAK inhibitors, or S1Ps, 16.1% of those in the guselkumab group achieved clinical remission compared with 3.6% of those in the placebo group (P = .005).

“In terms of symptomatic remission at week 12, the difference between the overall guselkumab result and placebo was 30%,” reported Peyrin-Biroulet.

Clinical response — defined as a decrease in the modified Mayo score by ≥ 30% and ≥ 2 points, with either a ≥ 1-point decrease from baseline in the rectal bleeding subscore or a rectal bleeding subscore of 0 or 1 — was 65.6% in the guselkumab group compared with 34.5% in the placebo group (P < .001).

Among patients naive to biologics, JAK inhibitors, or S1Ps, clinical response was 71.3% in the guselkumab group, compared with 41.8% in the placebo group (P < .001). Among those who had previously received biologics, JAK inhibitors, or S1Ps, it was 57.1% in the guselkumab group, compared with 25.0% in the placebo group (P < .001).

Turning to endoscopic improvement (ie, an endoscopic subscore of 0 or 1 with no friability), 37.3% of those in the guselkumab group overall, compared with 12.9% of those in the placebo group who achieved this endpoint (P < .001).

“This is a treatment effect of over 20%,” said Peyrin-Biroulet. “We know that when it is over 20%, it is considered game changer.”

In patients naive to biologics, JAK inhibitors, or S1Ps, endoscopic improvement was 45.7% with guselkumab vs 17.7% with placebo. In those who had previously received biologics, JAK inhibitors, or S1Ps, endoscopic improvement was 24.1% with guselkumab vs 7.1% with placebo. Both were statistically significant.

The safety of subcutaneous induction therapy was consistent with the well-characterized and favorable safety profile of guselkumab in approved indications.

 

The GRAVITI Study

In the phase 3, randomized, double-blind, placebo-controlled GRAVITI study, also presented at ECCO 2025 Congress, researchers evaluated the efficacy and safety of induction with subcutaneous guselkumab followed by subcutaneous maintenance compared with placebo in patients with moderately to severely active Crohn’s disease.

The GRAVITI study followed the same induction and maintenance dosage and treatment intervals as the ASTRO study.

In addition, the patients randomly assigned to placebo were able to receive subcutaneous guselkumab (400 mg every 4 weeks followed by 100 mg every 8 weeks) if rescue criteria were met at week 16.

The co-primary endpoints were clinical remission and endoscopic response at week 12.

Ailsa Hart, MD, director, IBD Research, and consultant gastroenterologist, St. Mark’s Hospital and Imperial College, both in London, reported the 12-week and 48-week results, which were initially presented at the American College of Gastroenterology (ACG) meeting in October 2024.

At week 12, 56.1% of patients who received guselkumab achieved clinical remission, compared with 21.4% of patients who received placebo. Endoscopic response was achieved in 41.3% of patients treated with guselkumab compared with 21.4% in the placebo group.

Regarding the 48-week results, Hart noted that the rate of clinical remission was more than three times higher with both maintenance doses of guselkumab at 66.1% (200 mg) and 60.0% (100 mg) vs 17.1% with placebo.

Endoscopic response at 48 weeks was achieved in 51.3% of patients on the 200-mg maintenance dose and in 44.3% on the 100-mg maintenance dose, compared with 6.8% of patients on placebo.

In addition, endoscopic remission was achieved in 38.3% of patients in the 200-mg guselkumab group and in 30.4% in the 100-mg guselkumab group, compared with 6.0% in the placebo group.

Safety findings were consistent with the known safety profile of guselkumab in approved indications and other studies in IBD.

“These results complement the GALAXI data and demonstrate that both IV and subcutaneous guselkumab induction are efficacious and therapeutic in Crohn’s disease,” Hart said. Furthermore, data from the ASTRO study demonstrated similar data in the UC population.

As clinicians, this gives us flexibility in how we treat our patients; although, the rationale for choosing subcutaneous or IV is likely to be pragmatic, Hart said.

Additionally, the flexibility of the maintenance therapy, that is, 200 mg subcutaneous guselkumab every 4 weeks or 100 mg every 8 weeks, “is expected to positively affect several parameters of therapy, including increased compliance, hospital avoidance, and better safety profiling,” comoderator Giorgos Bamias, MD, professor of gastroenterology at the School of Medicine, National and Kapodistrian University of Athens, said in an interview.

It appears that multiple options will be offered to patients regarding treatment with guselkumab for patients with Crohn’s disease, Bamias said. “Interestingly, a similar multiplicity of options has also been shown for ulcerative colitis, through the QUASAR and ASTRO studies.”

Peyrin-Biroulet declared receiving grants and other/support travel from multiple companies. Hart declared receiving grants and personal fees from multiple companies. Bamias declared receiving grants and personal fees/honoraria as an advisor/lecturer from multiple companies.

A version of this article appeared on Medscape.com.

BERLIN — Induction therapy with subcutaneous guselkumab demonstrated significant efficacy in patients with moderately to severely active ulcerative colitis (UC), according to results from the phase 3, randomized, double-blind, placebo-controlled ASTRO study.

Importantly, the study also showed that subcutaneous induction is consistent with intravenous (IV) induction of guselkumab in UC.

“The flexibility of a fully subcutaneous treatment regimen would be a welcome option for many patients, especially those with busy and active lifestyles,” said study lead Laurent Peyrin-Biroulet, MD, head of the inflammatory bowel disease (IBD) unit at University Hospital of Nancy, France.

Peyrin-Biroulet presented the results at European Crohn’s and Colitis Organisation (ECCO) 2025 Congress.

“I think it’s an evolution and improvement in terms of IBD management,” he said. “We are happy that our patients will have the choice.”

Guselkumab is a selective dual-acting interleukin (IL)–23p19 subunit inhibitor that potently blocks IL-23 and binds to CD64, a receptor on cells that produce IL-23, and is the only full subcutaneous IL-23 available. The drug is approved in some countries, including the United States, for UC.

 

The ASTRO Study

Building on data from the QUASAR studies, which showed the efficacy of induction of IV guselkumab and subcutaneous maintenance in patients with UC, the ASTRO study randomly assigned 418 patients with moderately to severely active UC to receive either induction with 400 mg subcutaneous guselkumab at weeks 0, 4, and 8 or placebo.

After induction, the treatment group either received a maintenance dose of 200 mg subcutaneous guselkumab at week 12 and then every 4 weeks or 100 mg every 8 weeks (starting week 16).

All patients had an inadequate response or intolerance to conventional therapy. Around 60% were naive to biologics, Janus kinase (JAK) inhibitors, or sphingosine-1-phosphate receptor modulators (S1Ps).

Clinical remission at week 12 — the primary endpoint — was achieved by 27.6% of all patients treated with guselkumab compared with 6.5% of patients on placebo (P < .001).

“These results are in line with the QUASAR data,” in which clinical remission was 22.6% with IV guselkumab at 12 weeks, noted Peyrin-Biroulet.

The researchers also divided the results by prespecified subgroups based on previous treatments.

Clinical remission was achieved at week 12 by 36% of patients naive to biologics, JAK inhibitors, or S1Ps in the guselkumab group and by 8.9% of these patients in the placebo group (P < .001). Among patients who had previously received biologics, JAK inhibitors, or S1Ps, 16.1% of those in the guselkumab group achieved clinical remission compared with 3.6% of those in the placebo group (P = .005).

“In terms of symptomatic remission at week 12, the difference between the overall guselkumab result and placebo was 30%,” reported Peyrin-Biroulet.

Clinical response — defined as a decrease in the modified Mayo score by ≥ 30% and ≥ 2 points, with either a ≥ 1-point decrease from baseline in the rectal bleeding subscore or a rectal bleeding subscore of 0 or 1 — was 65.6% in the guselkumab group compared with 34.5% in the placebo group (P < .001).

Among patients naive to biologics, JAK inhibitors, or S1Ps, clinical response was 71.3% in the guselkumab group, compared with 41.8% in the placebo group (P < .001). Among those who had previously received biologics, JAK inhibitors, or S1Ps, it was 57.1% in the guselkumab group, compared with 25.0% in the placebo group (P < .001).

Turning to endoscopic improvement (ie, an endoscopic subscore of 0 or 1 with no friability), 37.3% of those in the guselkumab group overall, compared with 12.9% of those in the placebo group who achieved this endpoint (P < .001).

“This is a treatment effect of over 20%,” said Peyrin-Biroulet. “We know that when it is over 20%, it is considered game changer.”

In patients naive to biologics, JAK inhibitors, or S1Ps, endoscopic improvement was 45.7% with guselkumab vs 17.7% with placebo. In those who had previously received biologics, JAK inhibitors, or S1Ps, endoscopic improvement was 24.1% with guselkumab vs 7.1% with placebo. Both were statistically significant.

The safety of subcutaneous induction therapy was consistent with the well-characterized and favorable safety profile of guselkumab in approved indications.

 

The GRAVITI Study

In the phase 3, randomized, double-blind, placebo-controlled GRAVITI study, also presented at ECCO 2025 Congress, researchers evaluated the efficacy and safety of induction with subcutaneous guselkumab followed by subcutaneous maintenance compared with placebo in patients with moderately to severely active Crohn’s disease.

The GRAVITI study followed the same induction and maintenance dosage and treatment intervals as the ASTRO study.

In addition, the patients randomly assigned to placebo were able to receive subcutaneous guselkumab (400 mg every 4 weeks followed by 100 mg every 8 weeks) if rescue criteria were met at week 16.

The co-primary endpoints were clinical remission and endoscopic response at week 12.

Ailsa Hart, MD, director, IBD Research, and consultant gastroenterologist, St. Mark’s Hospital and Imperial College, both in London, reported the 12-week and 48-week results, which were initially presented at the American College of Gastroenterology (ACG) meeting in October 2024.

At week 12, 56.1% of patients who received guselkumab achieved clinical remission, compared with 21.4% of patients who received placebo. Endoscopic response was achieved in 41.3% of patients treated with guselkumab compared with 21.4% in the placebo group.

Regarding the 48-week results, Hart noted that the rate of clinical remission was more than three times higher with both maintenance doses of guselkumab at 66.1% (200 mg) and 60.0% (100 mg) vs 17.1% with placebo.

Endoscopic response at 48 weeks was achieved in 51.3% of patients on the 200-mg maintenance dose and in 44.3% on the 100-mg maintenance dose, compared with 6.8% of patients on placebo.

In addition, endoscopic remission was achieved in 38.3% of patients in the 200-mg guselkumab group and in 30.4% in the 100-mg guselkumab group, compared with 6.0% in the placebo group.

Safety findings were consistent with the known safety profile of guselkumab in approved indications and other studies in IBD.

“These results complement the GALAXI data and demonstrate that both IV and subcutaneous guselkumab induction are efficacious and therapeutic in Crohn’s disease,” Hart said. Furthermore, data from the ASTRO study demonstrated similar data in the UC population.

As clinicians, this gives us flexibility in how we treat our patients; although, the rationale for choosing subcutaneous or IV is likely to be pragmatic, Hart said.

Additionally, the flexibility of the maintenance therapy, that is, 200 mg subcutaneous guselkumab every 4 weeks or 100 mg every 8 weeks, “is expected to positively affect several parameters of therapy, including increased compliance, hospital avoidance, and better safety profiling,” comoderator Giorgos Bamias, MD, professor of gastroenterology at the School of Medicine, National and Kapodistrian University of Athens, said in an interview.

It appears that multiple options will be offered to patients regarding treatment with guselkumab for patients with Crohn’s disease, Bamias said. “Interestingly, a similar multiplicity of options has also been shown for ulcerative colitis, through the QUASAR and ASTRO studies.”

Peyrin-Biroulet declared receiving grants and other/support travel from multiple companies. Hart declared receiving grants and personal fees from multiple companies. Bamias declared receiving grants and personal fees/honoraria as an advisor/lecturer from multiple companies.

A version of this article appeared on Medscape.com.