SpringWorks Therapeutics, Inc. announced that the U.S. Food and Drug Administration (FDA) has approved OGSIVEO? (nirogacestat), an oral gamma secretase inhibitor, for the treatment of adult patients with progressing desmoid tumors who require systemic treatment. The FDA previously granted breakthrough therapy, fast track and orphan drug designations to nirogacestat for the treatment of desmoid tumors.  Desmoid tumors are locally aggressive and invasive soft-tissue tumors that can lead to substantial morbidity.

In addition, when vital structures are impacted, desmoid tumors can be life-threatening. Although they do not metastasize, desmoid tumors are often refractory to existing off-label systemic therapies and associated with recurrence rates of up to 77% following surgical resection. Desmoid tumor experts and treatment guidelines now recommend systemic therapies as first-line intervention instead of surgery for most tumor locations requiring treatment. The FDA approval of OGSIVEO is based on the results from the Phase 3 DeFi trial, which were published in the March 9, 2023 edition of the New England Journal of Medicine.7 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).

Median PFS was not reached in the OGSIVEO arm and was 15.1 months in the placebo arm. Confirmed objective response rate (ORR) based on RECIST v1.1 was 41% with OGSIVEO versus 8% with placebo (p<0.001); the complete response rate was 7% in the OGSIVEO arm and 0% in the placebo arm. The median time to first response was 5.6 months with OGSIVEO and 11.1 months with placebo. PFS and ORR improvements were in favor of OGSIVEO regardless of baseline characteristics including sex, tumor location, tumor focality, treatment status, previous treatments, mutational status, and history of familial adenomatous polyposis. OGSIVEO also demonstrated early and sustained improvements in patient-reported outcomes (PROs), including pain (p<0.001), desmoid tumor-specific symptoms (p<0.001), physical/role functioning (p<0.001), and overall health-related quality of life (p=0.01).

OGSIVEO exhibited a manageable safety and tolerability profile. The most common adverse events (>15%) reported in patients receiving OGSIVEO were diarrhea, ovarian toxicity, rash, nausea, fatigue, stomatitis, headache, abdominal pain, cough, alopecia, upper respiratory tract infection, and dyspnea. Please see Important Safety Information below, including Warnings & Precautions relating to diarrhea, ovarian toxicity, hepatotoxicity, non-melanoma skin cancers, electrolyte abnormalities, and embryo-fetal toxicity.