[1] The most common side effects include diarrhea, ovarian toxicity, rash, nausea, fatigue, stomatitis, headache, abdominal pain, cough, alopecia, upper respiratory tract infection and dyspnea.

[1][2] The effectiveness of nirogacestat was evaluated in DeFi (NCT03785964), an international, multicenter, randomized (1:1), double-blind, placebo-controlled trial in 142 adult participants with progressing desmoid tumors not amenable to surgery.

[2] The main efficacy outcome measure was progression-free survival (the length of time after the start of treatment for which a person is alive and their cancer does not grow or spread).

[7][needs update] In addition, a phase III clinical trial, DeFi, was in progress for nirogacestat for adults with desmoid tumors and aggressive fibromatosis.

[9][10][11] The FDA granted the application for nirogacestat priority review, fast track, breakthrough therapy, and orphan drug designations.