Merck announced on Aug. 4 that its experimental anti-TL1A antibody, tulisokibart, recorded both a failure and a success in recent clinical trials following its acquisition of Prometheus Biosciences. The monoclonal antibody did not meet the main goal in a Phase 2 trial for patients with systemic sclerosis-associated interstitial lung disease, leading Merck to discontinue the study. No new safety concerns were identified during the trial, which enrolled 154 patients.
In contrast, Merck reported positive results for tulisokibart in treating hidradenitis suppurativa. The company said the Phase 2b trial met both primary and key secondary endpoints but did not disclose detailed data. Full results are expected to be presented at an upcoming medical conference. This study involved 147 participants and measured reductions in skin abscesses and inflammatory nodules.
Tulisokibart was acquired by Merck as part of its $10.8 billion purchase of Prometheus Biosciences in 2023. The drug is also known as MK-7240 and was seen as a key asset for potential treatment of ulcerative colitis and Crohn’s disease.
Earlier this summer, Merck shared that tulisokibart achieved clinical remission for ulcerative colitis patients in a Phase 3 trial but withheld specific data points. Analysts have expressed caution about the drug’s prospects due to limited information and competition from Roche’s afimkibart, which can be administered subcutaneously rather than intravenously like tulisokibart.
Dean Li, head of research and development at Merck, said on an Aug. 4 investor call, “We look forward to the upcoming readout of the larger induction and maintenance study, which, together with the induction-only study, would form the basis of a regulatory filing and will be presented at an upcoming scientific congress.” Li added that late-stage results reinforce “the potential of targeting TL1A to help address immunofibrosis.”
Merck reported second-quarter sales totaling $16.6 billion—above consensus estimates—and raised its fiscal year sales guidance slightly to $66.8 billion midpoint. The company also narrowed earnings per share projections due to costs associated with acquiring Terns Pharmaceuticals.
