Overview

• The authorization covers the oral gamma secretase inhibitor as monotherapy for adults with progressing desmoid tumors who require systemic treatment.
• In the phase 3 DeFi trial, nirogacestat achieved a progression‑free survival hazard ratio of 0.29 versus placebo and an objective response rate of 41% compared with 8%.
• Participants reported early, sustained improvements in pain, desmoid‑specific symptoms, physical and role functioning, and overall health‑related quality of life.
• Pooled safety data showed common adverse reactions including diarrhea (85%), rash (65%), ovarian toxicity in women of childbearing potential (60%), nausea (59%), fatigue (50%), hypophosphatasemia (50%), headache (40%) and stomatitis (40%).
• The drug already holds U.S. approval and Orphan Drug designation from both FDA and EMA, and Merck signaled a European launch alongside its newly approved therapy for NF1‑PN.