Core Insights - Long-term treatment with OGSIVEO (nirogacestat) for up to 4 years demonstrated further tumor size reductions, increased objective response rates, sustained improvement in desmoid tumor symptoms, and a consistent safety profile [1][3][5] Efficacy and Safety - The Phase 3 DeFi trial showed significant improvements in progression-free survival (PFS), objective response rate (ORR), and patient-reported outcomes (PRO) in adult patients with progressing desmoid tumors [2][6] - The median duration of OGSIVEO treatment was 33.6 months, with ORR increasing from 34.3% in year 1 to 45.7% for patients treated for up to 4 years [3][6] - The median best percent reduction in target tumor size was −32.3% at year one and −75.8% for patients completing at least four years of treatment [3] Patient-Reported Outcomes - Improvements in PROs related to pain, symptom severity, physical functioning, global health status, and role functioning were observed early and sustained through treatment [3] Adverse Events - The incidence and severity of treatment-emergent adverse events (TEAEs) decreased over the treatment duration, with common adverse events including diarrhea, ovarian toxicity, rash, and nausea [4][21] - Serious adverse reactions occurred in ≥2% of patients, with ovarian toxicity being the most notable [21] Background on Desmoid Tumors - Desmoid tumors are rare, locally aggressive tumors that can cause significant pain and functional impairment, with a prevalence of up to 1650 new cases diagnosed annually in the U.S. [7][8] - Systemic therapies are now recommended as first-line interventions for most desmoid tumor locations requiring treatment [8] About OGSIVEO - OGSIVEO is an oral gamma secretase inhibitor approved for the treatment of adult patients with progressing desmoid tumors requiring systemic treatment, with Orphan Drug designation granted by the FDA and EMA [9]