The FDA has approved Ogsiveo (Nirogacestat) tablets for adult patients with progressing desmoid tumors who require systemic treatment. Ogsiveo is the first drug to be approved for the treatment of patients with desmoid tumors, a rare subtype of soft tissue sarcomas. The FDA approval of Ogsiveo is based on the results from the Phase 3 DeFi trial. The results showed that Ogsiveo met the primary endpoint of improving progression-free survival (PFS), demonstrating a statistically significant improvement over placebo with a 71% reduction in the risk of disease progression (hazard ratio (HR) = 0.29 (95% CI: 0.15, 0.55); p< 0.001). Ogsiveo is an oral, selective, small molecule gamma secretase inhibitorγ. Gamma secretase cleaves multiple transmembrane proteins, including Notch, that are believed to play a role in activating pathways that contribute to growth of desmoid and ovarian granulosa cell tumors.