Pharma BD Deal Intelligence
Merck acquired Prometheus Biosciences for approximately $10.8 billion ($200.00 per share in cash; announced April 16, 2023, completed June 16, 2023), gaining PRA023 — now branded tulisokibart (MK-7240), a humanized anti-TL1A monoclonal antibody — to strengthen its immunology pipeline. The lead Phase 2 ARTEMIS-UC ulcerative colitis study (published in NEJM, September 26, 2024) showed clinical remission of 26% with tulisokibart versus 1% with placebo at week 12. Post-close, Merck advanced the asset into a two-study Phase 3 IBD program — ATLAS-UC in ulcerative colitis and ARES-CD in Crohn's disease (UC preliminary readout expected November 2026) — and on October 6, 2025 expanded development into three additional immune-mediated inflammatory diseases (hidradenitis suppurativa, radiographic axial spondyloarthritis, and rheumatoid arthritis) via new Phase 2b trials.