Promising New Data for Novel, Established Drugs for Common GI Conditions

 Hello. I’m Dr David Johnson, professor of medicine and chief of gastroenterology at Eastern Virginia Medical School in Norfolk, Virginia. 

I’ve just returned from the American College of Gastroenterology (ACG) 2024 Annual Scientific Meeting, which this year was held in Philadelphia, Pennsylvania. 

In this series, I’ll be giving you my top studies presented at ACG 2024, which will be split into two parts. These studies are not presented in any order of priority because I think they all have clinical applications, some of which are more immediate. Where possible, I’ll also provide you with some teaching points that occurred to me when I viewed the data in these presentations. 

Repetitive Use Injuries Among Endoscopists 

First is a study that assessed musculoskeletal injuries that occurred while performing endoscopy, which is a large part of what we do as gastroenterologists. I’ve personally experienced virtually all these injuries during my 45-plus years in the field. These findings provide a useful perspective of what we can do to potentially avoid such injuries going forward. 

This study comes to us from researchers at the University of Utah,^[1] who looked at an author- developed and validated questionnaire called QuickDash (Disability of Arm, Shoulder, Hand). Endoscopists were evaluated by occupational therapists in their department, who looked at strength testing as well as a series of provocative tests to identify injuries.

Thirty-five endoscopists were enrolled. Overall, 34% reported experiencing pain and 17% reported numbness. In the previous week, 48% had been bothered by pain and 11% by tingling, and 17% reported limitations on what they could do at work. 

Additionally, 17% experienced interrupted sleep. I think that finding is particularly important, because when you have fragmented sleep it lowers sensory thresholds. Essentially, this means that the day after interrupted sleep, you respond with a heightened sensory response. 

Physical testing showed reduction in grip strength in approximately half of participants, including both right and left grip. More than 70% had at least one abnormal positive provocative test.

There were a couple factors associated with an increased risk for adverse outcomes. Those who performed 20 or more procedures a week were at higher risk of pain (P = .007). I recognize that some of you probably perform 20 or more endoscopies in a single day. 

Negative outcomes were also more likely to occur among physicians performing biliary endoscopy. Performing endoscopic retrograde cholangiopancreatography during 20%-60% of the week resulted in greater likelihood of experiencing decreased bilateral pinch strength. 

The bottom line is that there’s an extremely high prevalence of repetitive use injury among endoscopists. Whether you’re just starting out, mid-career, or more senior, you need to be aware of this. 

Kudos to the ACG who put together hands-on sessions across 2 days with extended ergonomics training provided by physical therapists with expertise in this area. These sessions were standing room only every time I visited them.

During the meeting, the ACG also announced the publication of a new book, Ergonomics for Endoscopy: Optimal Preparation, Performance, and Recovery, that is available on the ACG’s website. I had the privilege to meet the two authors, survey the book, and briefly discuss it with them. It’s phenomenal, and something that I think every endoscopist can benefit from. 

So, in summary, don’t put aside these concerns. It’s your career, and the better we can do in preventing these injuries, I think the better you’ll feel going forward. 

On-Demand Vonoprazan for Heartburn 

The second study of note^[2] dealt with vonoprazan, a potassium-competitive acid blocker.

The question surrounding vonoprazan is whether it has clinical value as an on-demand option rather than simply as maintenance therapy administered via daily dosing. Previous results have suggested that it may have a more rapid effect when it’s taken on demand. 

This post hoc analysis of a randomized trial evaluated a 4-week run-in period during which patients received vonoprazan 20 mg daily, followed by a 6-week period after which patients switched to on-demand therapy. To be eligible, during the run-in period patients had to be 80% compliant with the study drug and report no heartburn during the last 7 days of treatment. If so, they were then randomized to receive vonoprazan at 10 mg, 20 mg, or 40 mg, or placebo.

Eligible patients reported 16% heartburn-free days during the screening period. During the run-in period, heartburn-free days increased to 83% among those taking vonoprazan 20 mg daily. When this was stopped and patients transitioned to on-demand vonoprazan, they still had a very high rate of heartburn-free days, ranging from 71% to 75%. Over 90% in the treatment group had their symptoms improved within 2 hours, with improvement noted as early as within 1 hour. 

We know that proton-pump inhibitors don’t produce this effect, which presents a challenge for us. This study suggests there may be a very strong role for on-demand therapy in patients who have reflux, which certainly showed in terms of responsiveness during the 4-week run-in period.

Rifaximin Monotherapy Reduces Risk for Overt Hepatic Encephalopathy Recurrence

The next trial^[3] looked at rifaximin monotherapy for prevention of relapse of overt hepatic encephalopathy. 

Rifaximin has been added to the baseline primary treatment of lactulose, a combination that has been analyzed in pivotal studies. However, lactulose is a difficult drug to titrate. We typically ask patients to let us know if they have Bristol Stool Scale scores ≥ 6. This results in an inordinate number of calls back to the clinic or office. Diarrhea is a particular problem in these patients. 

This study, which was presented by Dr Jasmohan S. Bajaj from Virginia Commonwealth University, analyzed data from two randomized trials: a phase 3 double-blind trial and a phase 4 open-label trial. Both studies were conducted in patients with Child-Pugh classification A and B cirrhosis, whose overt hepatic encephalopathy was graded with a Conn score ≤ 1. Researchers only looked at those patients who received rifaximin 550 mg twice daily without lactulose, or lactulose titrated to a target of two to three soft stools a day plus placebo. The primary endpoint, which was used in both trials, was time to first breakthrough overt hepatic encephalopathy episode, measured as a Conn score ≥ 2.

There were 125 patients in the rifaximin group and 145 patients in the lactulose group. Patients in both groups had mean age of 57 years and a median Model for End-Stage Liver Disease score of 12. 

Treatment with rifaximin produced significantly striking results. In the rifaximin group, the risk for breakthrough overt hepatic encephalopathy episodes was reduced by 60%, with a number needed to treat of 4, which is extremely powerful. Regarding mortality reduction, the number needed to treat with rifaximin alone was 19. 

The take-away message here is that it’s difficult to use lactulose. We frequently have to stop it. These results provide reassurance that rifaximin has a dramatic effect even when used by itself. The recommended first-line therapy is still to begin with lactulose, but this study provides us with very strong data regarding the use of rifaximin alone. 

Apraglutide’s Efficacy in Short-Bowel Syndrome 

The fourth study^[4] I’d like to highlight adds to the growing data around a long-acting glucagon-like peptide 2 analog, apraglutide.

Results from the phase 3, double-blind STARS trial were first presented at Digestive Disease Week earlier in the year. They showed that apraglutide had efficacy and contributed to a reduction in the risk for needing parenteral support, maintenance of weight, and fluid requirements in patients with short-bowel syndrome and intestinal failure. However, questions remained regarding whether there were variations in response based on patient demographics and short-bowel syndrome–specific characteristics. 

Researchers looked at a subgroup of patients from the STARS trial. The primary endpoint remained the same as in the main trial: relative change from baseline in actual parenteral support weekly volume at week 24. However, rather than measure it in the overall population, they did so according to geographic region, gender, age, body weight, race and ethnicity, and short-bowel syndrome characteristics, including differences in parenteral support volume, length of the remnant small intestine, and time from short-bowel syndrome diagnosis.

Across all these demographic and disease characteristic categories, there was absolutely no difference in the primary endpoint. 

Apraglutide seems to be inordinately promising. This is a once-weekly treatment, as opposed to liraglutide, which is problematic because it has to be given daily. 

From what I understand, apraglutide has been offered a fast-track status by the US Food and Drug Administration. Again, from what I’ve heard, it will be evaluated upon submission beginning sometime in the first quarter of 2025, which may mean that apraglutide could be available as early as 2026. 

This would be a big deal for patients with short-bowel syndrome who would have a once-weekly treatment option as opposed to daily treatment and its accompanying problems of compliance and relatively reduced response.

Biologics for Treating Immune Checkpoint Inhibitor Colitis

The final study^[5] I want to discuss in this presentation dealt with adverse responses to immune checkpoint inhibitor (ICI) therapy. We see this increasingly in our clinics as ICIs become more widely used. They are wonderful drugs, but ICI-induced colitis can occur in up to 30% of patients. 

The oncologic approach is to try and stay the course, while gastroenterologists are tasked with treating the colitis so that these patients can maintain their cancer treatment. Steroid therapy is the primary first-line treatment against ICI colitis, but the use of biologic therapy with infliximab or vedolizumab has been associated with favorable outcomes as well. 

ICI colitis is graded on a scale. Whereas grade 1 ICI colitis indicates increased stool frequency of less than four a day and the absence of symptoms, grade 2 indicates a progression to a stool frequency of 4 to 6 times a day, the appearance of blood or mucus in the stool, and symptoms like abdominal pain.

Researchers sought to answer the question of which treatment is better for patients with moderate to severe ICI colitis: infliximab or vedolizumab? They performed a database analysis of patients at their institution who received at least one dose of these biologics. The endpoint was sustained clinical response (ie, without a recurrent colitis episode), as well as patients achieving improvement to grade 1 ICI colitis.

The data for infliximab and vedolizumab were quite good. Sustained clinical response was noted in 91% of patients receiving infliximab and 86% receiving vedolizumab. There was no difference in infection risk between the groups. 

There’s a teaching point in the study’s other key finding, which is that following biologic initiation, steroids were more rapidly discontinued with vedolizumab vs infliximab (median, 25 days vs 56 days, respectively). Therefore, vedolizumab may have the added benefit of patients being able to get off steroids more quickly. That’s the take-home message: Vedolizumab may be better. We certainly are comfortable with both biologics, but patients getting off steroids would be better.

There are two additional teaching points I’d like to convey.

First, don’t forget to perform a biopsy, because there are patients who may have cytomegalovirus colitis and we don’t want to miss it. A biopsy may also reveal whether they have a macroscopically normal rectosigmoid. So, you should biopsy to look for microscopic changes. As 98% of ICI colitis cases involve the left colon, you can get by with just using a flexible sigmoidoscopy.

Second, don’t forget to check for celiac disease. Patients taking ICIs may develop celiac disease as a side effect of treatment. So, I always order a celiac profile as well. 

David A. Johnson, MD, a regular contributor to Medscape, is professor of medicine and chief of gastroenterology at Eastern Virginia Medical School in Norfolk, Virginia, and a past president of the American College of Gastroenterology. His primary focus is the clinical practice of gastroenterology. He has published extensively in the internal medicine/gastroenterology literature, with principal research interests in esophageal and colon disease, and more recently in sleep and microbiome effects on gastrointestinal health and disease. 

https://www.medscape.com/viewarticle/promising-new-data-drugs-both-novel-and-established-several-2024a1000kdv