Nirogacestat achieved primary and all key secondary endpoints in phase III DeFi Trial in adult patients with progressing desmoid tumors.

The DeFi trial met its primary endpoint of improving progression-free survival (PFS), demonstrating a statistically significant improvement for nirogacestat 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). In addition, the trial met all key secondary endpoints, with nirogacestat demonstrating statistically significant improvements as compared to placebo in objective response rate (ORR) and patient-reported outcomes (PROs). Nirogacestat was generally well tolerated with a manageable safety profile. The majority of women of childbearing potential had adverse events consistent with ovarian dysfunction. Other adverse events were generally consistent with previously reported data.

Additional data are expected to be presented at an upcoming medical conference in the second half of 2022 and SpringWorks plans to submit a New Drug Application (NDA) to the FDA in the second half of 2022.

Desmoid tumors are rare, aggressive, locally invasive, and potentially morbid tumors of the soft tissues. While they do not metastasize, desmoid tumors are associated with a high rate of recurrence. Sometimes referred to as aggressive fibromatosis, or desmoid fibromatosis, these soft tissue tumors can be serious, debilitating, and, in rare cases when vital organs are impacted, they can be life-threatening.

Historically, desmoid tumors were treated with surgical resection, but this approach has become less favored due to a high recurrence rate after surgery. There are currently no FDA-approved therapies for the treatment of desmoid tumors.