11 Studies to Know From ACG 2021

COMMENTARY

11 Studies to Know From ACG 2021

David A. Johnson, MD

Disclosures

November 04, 2021

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This transcript has been edited for clarity.

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 annual meeting of the American College of Gastroenterology (ACG), which was recently reported to be the largest gastroenterology association in the world. This year's meeting was held in Las Vegas, live and in person, although there was a hybrid combination of virtual and onsite presence. It was so good to reconnect with colleagues and not have it be on a Zoom call.

ACG 2021 featured around 3500 abstracts, plenaries, and poster presentations. I've reviewed nearly all of them in order to give you my perspectives on the findings I believe to have the greatest practice-changing implications going forward.

Using Adenomas per Colonoscopy for Detecting Colorectal Cancer

Dr Joseph Anderson and colleagues from New Hampshire compared mean adenomas per colonoscopy vs the adenoma detection rate (ADR) as a quality measure for interval cancer protection.[1] They evaluated 9023 colonoscopies from 138 endoscopists to assess for interval colorectal cancer diagnosed within 3 years.

They found that adenoma per colonoscopy may be as discriminant for interval cancer protection as ADR. An adenoma per colonoscopy cutoff of 0.4 per screening colonoscopy was on par with an ADR of 25%, which is conventionally recognized as the minimum threshold for a mixed-gender population. Increasing the adenoma per colonoscopy cutoff to 0.6 further improved outcomes by about a third.

In light of these results, I'd expect the guideline committees to consider evaluating adenoma per colonoscopy a little bit more. It perhaps makes more sense that rather than a one-and-done adenoma approach, you should be evaluating how many you actually detect over the course of the colonoscopy.

Evaluating Immunotherapy-Mediated Colitis

Immunotherapy-mediated colitis is an adverse event that ranges from mild to moderate in severity, and which we increasingly encounter as immune checkpoint inhibitors are expanded to treat cancers of the skin, breast, lung, and other indications. The question is, do you need a full colonoscopy to make the diagnosis?

In a cross-sectional, single-center study,[2] researchers analyzed 52 symptomatic patients taking immune checkpoint inhibitors to compare the value of colonoscopy vs a left-sided sigmoidoscopy exam. They found that the sigmoidoscopy diagnosed 100% of patients with immunotherapy-mediated colitis. There was no additional value gained by performing biopsies more proximally.

The teaching points here are that biopsies should be taken from both normal and abnormal mucosa, and that flexible sigmoidoscopy may save patients from having to have a full colonoscopy.

New Data on Ozanimod

There were two presentations on ozanimod, a new treatment for moderate to severe ulcerative colitis approved by the US Food and Drug Administration in May 2021. Ozanimod is an oral sphingosine 1-phosphate receptor modulator administered at a 1 mg daily dose, which is very promising for our patients with ulcerative colitis.

The first presentation,[3] which was given by Dr Bruce Sands of Mount Sinai in New York City, drew on data from a phase 3 trial assessing the efficacy and safety of ozanimod up to 52 weeks. In a post-hoc analysis, researchers evaluated the impact of prior biologic exposure on the response to ozanimod. The results indicated that prior biologic exposure was not a meaningful predictor for clinical response to ozanimod. It may have taken longer to get a response among those previously exposed to biologics; nonetheless, ozanimod showed a very promising sustained effect at up to 52 weeks in these patients.

The second presentation[4] was given by Dr Marla Dubinsky, also from Mount Sinai, and offered a follow-up on ozanimod's efficacy and safety over a 52-week window. There are no head-to-head randomized controlled trials with this agent vs other conventional biologics. In the absence of this, researchers used a matching-adjusted indirect comparison with other studies of comparable design. They determined that ozanimod had a superior safety profile to adalimumab at both induction and maintenance. Ozanimod was comparable to vedolizumab at induction, but better over maintenance therapy.

With a new therapy such as this, it's reassuring to see the positive safety profiles extending out for up to a year.

Risankizumab for Crohn's Disease

We have another exciting new agent in the treatment of inflammatory bowel disease. Risankizumab is a humanized immunoglobulin G1 monoclonal antibody against the p19 subunit of interleukin-23.

Dr David Rubin from the University of Chicago presented results from dual double-blind, placebo-controlled, randomized, multicenter phase 3 trials of risankizumab in moderate to severe Crohn's disease.[5]

There was no difference shown between two doses of intravenous risankizumab. However, the Crohn's disease activity index and a composite endpoint, including endoscopic assessment, showed that there was sustained and seemingly increased benefit, both in remission and response, through 12 weeks of treatment.

Biologic therapy seemed to be a bit laggard if you had inadequate or no response to prior biologic therapies going into this trial.

We should keep in mind that these are only 12-week data and we'll need to see more. That being said, I think this treatment is extremely promising for moderate to severe Crohn's disease.

Emerging Microbiome Data

There were two very interesting presentations on the subject of the microbiome.

The first was a randomized, placebo-controlled trial looking at the relapse of Clostridioides difficile.[6] Dr Jessica Allegretti and colleagues studied a new oral microbiome therapy in patients at high risk for C difficile recurrence. After receiving initial antibiotic treatment, patients underwent a 2-day washout period and were then randomized to receive either the oral therapy or placebo without a bowel preparation. The primary endpoint was sustained clinical cure at week 8.

They found that use of the oral therapy was associated with a statistically significant benefit of approximately 13%. This would translate into a number-needed-to-treat of around 7 to 8.

These results indicate that this intervention does seem to change microbial diversity. It therefore represents a new potential therapy that, once approved, may prove helpful for preventing C difficile relapse in such patients.

The second study[7] set forth an interesting therapeutic concept by using fecal microbiota transplants (FMT) for hepatic encephalopathy. Researchers from the University of Michigan looked at 10 patients who received FMT capsules derived from five healthy donors, administered five times over 3 weeks.

The investigators looked at the 6-month composite scores for hepatic encephalopathy and showed that there was a significant benefit for the patients receiving FMT. This positive effect didn't seem to correlate with changes in Model for End-Stage Liver Disease scores or venous ammonia scores among those receiving FMT. These patients were also receiving rifaximin and lactulose, so the effect seems to be additive to those current standards as well.

Predicting Relapse Following TIPS Placement

Renal function is something that we don't traditionally use to predict relapse following transjugular intrahepatic portosystemic shunt (TIPS)-related hepatic encephalopathy.

Researchers assessed the value of stratifying relapse risk by glomerular filtration rate (GFR) in 201 patients receiving TIPS for refractory ascites, approximately 40% of whom met the criteria for chronic kidney disease; of these, 21% were hemodialysis dependent. They found that among those with a GFR < 30 at the time of TIPS, the odds ratio for hepatic encephalopathy was 3.5 times greater at 6 months.[8]

This indicates that perhaps we really need to get better at stratifying for prediction of hepatic encephalopathy in these patients. This stratification system may be a way of doing that, although further work is certainly needed.

Impact of Changing Age Recommendations for Colonoscopy

New guidelines have recommended lowering the age to initiate colorectal cancer screening to 45 years.

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