Tags: IBD, ulcerative colitis, immunology, TL1A, phase 3, Merck, MSD, Prometheus Biosciences, AbbVie, Sanofi, Teva, Roche, Takeda

MSD's TL1A drug tulisokibart delivers in pivotal IBD trial

By FieldPulse Editorial · June 23, 2026

Merck's tulisokibart delivered the first phase 3 remission result for a TL1A drug in ulcerative colitis, sharpening the IBD competitive race.

Merck has a new immunology story for field teams to track closely.

Pharmaphorum reported that tulisokibart, the TL1A antibody Merck gained through its 2023 acquisition of Prometheus Biosciences, became the first anti-TL1A biologic to help ulcerative colitis patients achieve clinical remission in a phase 3 trial.

In the pivotal ATLAS-UC induction-only trial, called Study 2, the drug significantly improved clinical remission rates versus placebo at 12 weeks in patients with moderate to severe ulcerative colitis, using the Modified Mayo Score.

This is important because tulisokibart has been one of the biggest commercial rationale points behind Merck's $10.8 billion Prometheus deal.

Pharmaphorum says analysts have projected the asset could eventually generate $4 billion to $5 billion in peak sales.

Positive phase 3 induction data do not equal approval, but they do strengthen the case that Merck is building a meaningful future position in inflammatory bowel disease rather than just running another early immunology experiment.

For GI and immunology field teams, the real significance is competitive.

TL1A has become one of the most watched targets in inflammation, and Merck now has an argument that it is in front of the pack.

The source says tulisokibart is racing alongside late-stage candidates including Teva and Sanofi's duvakitug and Roche's afimkibart.

Other companies are active earlier in development as well, but today's readout matters because it gives Merck the first phase 3 remission result in the class.

That should get attention from incumbent IBD players too.

While the source does not frame the story as an immediate launch threat to any single marketed product, it clearly supports a broader competitive interpretation: another major company is moving toward the IBD market with a differentiated mechanism that could reshape future treatment positioning.

Field teams at AbbVie, Takeda, J&J, and other companies with GI exposure should expect more questions over time abo.