4 Gastroenterology Headlines You Missed in June 2026

June brought continued momentum in gastroenterology, with late-stage clinical trial successes in ulcerative colitis, expanded treatment options for pediatric patients, and expert insights into the diagnosis of complex gastrointestinal disorders. Together, the month's developments highlighted ongoing innovation in inflammatory bowel disease while reinforcing the importance of timely recognition and multidisciplinary management across the spectrum of GI care.

Among the most notable updates were positive phase 3 results for the investigational therapies tulisokibart and obefazimod, both of which demonstrated meaningful efficacy in patients with moderately to severely active ulcerative colitis. Tulisokibart became the first anti-TL1A therapy to meet phase 3 endpoints in ulcerative colitis, while obefazimod showed durable remission in a highly refractory patient population, further expanding the pipeline of potential treatment options.

Beyond inflammatory bowel disease, clinicians gained additional perspective on the expanding pediatric indication for linaclotide in functional constipation and the diagnostic challenges posed by conditions such as hereditary angioedema, mast cell activation syndrome, and eosinophilic gastrointestinal disorders that can mimic more common GI conditions.

In this gastroenterology month in review, the editorial team of HCPLive Gastronerology highlights the key clinical trial updates, regulatory developments, and expert perspectives that shaped June.

Tulisokibart Meets Phase 3 Endpoints in Ulcerative Colitis, First for Anti-TL1A

On June 22, 2026, Merck announced positive topline results from the phase 3 ATLAS-UC induction-only study (Study 2) evaluating tulisokibart (MK-7240), an investigational humanized monoclonal antibody targeting tumor necrosis factor-like cytokine 1A (TL1A), in patients with moderately to severely active ulcerative colitis. The study successfully met its primary endpoint of clinical remission according to the Modified Mayo Score at week 12 as well as key secondary endpoints, with no new safety concerns identified.

Obefazimod Delivers Week 44 Remission in Refractory UC Patients

On June 29, 2026, Abivax SA announced topline results from ABTECT Maintenance Part 2, the supplemental portion of its phase 3 ulcerative colitis maintenance program evaluating obefazimod, an investigational oral miR-124 enhancer, in adults with moderately to severely active ulcerative colitis. Results showed obefazimod delivered meaningful clinical benefit in a highly refractory ulcerative colitis population, with 37.2% of induction non-responders achieving clinical remission and 34.5% achieving endoscopic remission at week 44 following continued 50 mg treatment.

FDA Expansion of Linaclotide for Children 2-5 Years With Functional Constipation

Following the May 27, 2026, US Food and Drug Administration expanded approval of Ironwood Pharmaceuticals' linaclotide (Linzess) for pediatric patients aged ≥2 years with functional constipation, the editorial team of HCPLive Gastroenterology spoke with Julie Khlevner, MD, a pediatric gastroenterologist at Columbia University Vagelos College of Physicians and Surgeons and an associate professor at Columbia University Medical Center. She spoke on the burden of functional constipation, the data supporting the expanded approval, and what the availability of this treatment means for patient care.

Abdominal Pain and Bloating: When to Consider HAE, MCAS, and EGIDs

While conditions like hereditary angioedema (HAE), mast cell activation syndrome (MCAS), and eosinophilic GI disorders can all present with episodic abdominal symptoms, they remain low on the radar of most primary care providers and even gastroenterologists seeing these patients first. Brian Lacy, MD, PhD, a board-certified gastroenterologist at the Mayo Clinic in Jacksonville, explained to HCPLive how he approaches this differential from the gastroenterology side and where collaboration with allergy and immunology becomes essential.