Pharma BD Deal Intelligence
Merck (NYSE: MRK) acquired Pandion Therapeutics in an all-cash tender offer of $60.00 per share, ~$1.85 billion, announced February 25, 2021 and completed April 1, 2021. The deal brought Pandion's TALON (bispecific tethered effector) platform and its lead asset PT101 (renamed MK-6194), an engineered IL-2 mutein designed to selectively expand regulatory T cells for autoimmune disease. Under Merck, MK-6194 advanced into Phase 2, including a Phase 2a study in non-segmental vitiligo (NCT06113328) and exploratory work in systemic lupus erythematosus and ulcerative colitis. In July 2025 Merck discontinued MK-6194 after a review of primary results from trial MK-6194-007 and exploratory Phase 1b data showed the candidate "did not confer clinical benefit" (Merck spokesperson); the move came amid a broader ~$3B cost-cutting program. The vitiligo study was terminated (status: Terminated, business reasons; primary completion March 2025). Phase 1 PK/PD data (ImmunoHorizons, March 2025) confirmed dose-dependent, Treg-selective expansion, but efficacy did not translate. The outcome leaves the $1.85B acquisition without a clinical asset to show for its core rationale.