BOTHELL, WASHINGTON, April 29, 2026
Immunome has announced the submission of a New Drug Application (NDA) to the U.S. Food and Drug Administration (FDA) for varegacestat, an investigational oral gamma secretase inhibitor (GSI), for the treatment of adults with desmoid tumors, a rare and debilitating soft tissue condition. The NDA is supported by compelling results from the Phase 3 RINGSIDE trial, which demonstrated statistically significant improvements in progression-free survival (PFS) and key secondary endpoints compared to placebo. This milestone positions varegacestat as a potential first-in-class targeted oral therapy, offering new hope for patients facing limited treatment options and high disease burden.
Phase 3 RINGSIDE Trial Demonstrates Strong Clinical Efficacy
The RINGSIDE Phase 3 clinical trial, a global randomized, double-blind, placebo-controlled study, evaluated the efficacy and safety of varegacestat in 156 patients with progressing desmoid tumors, marking the largest randomized study conducted in this patient population. The trial successfully met its primary endpoint, showing an 84% reduction in the risk of disease progression or death compared to placebo (hazard ratio = 0.16, p<0.0001), a highly significant outcome in oncology clinical research.
Additionally, varegacestat achieved a confirmed objective response rate (ORR) of 56%, compared to just 9% in the placebo group, further reinforcing its therapeutic potential. Exploratory analyses also revealed a median tumor volume reduction of 83%, highlighting the drug’s ability to deliver substantial disease control and clinical benefit. These findings underscore the importance of targeted molecular therapies in managing rare tumors, where treatment innovation remains critical.
Safety Profile and Patient-Centric Outcomes
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Beyond efficacy, varegacestat demonstrated a manageable and well-tolerated safety profile, consistent with the gamma secretase inhibitor class. The most commonly reported adverse events included diarrhea, fatigue, rash, nausea, and cough, with the majority being mild to moderate (Grade 1 or 2). Importantly, the trial also showed significant improvements in patient-reported outcomes, including reductions in pain intensity and tumor-related symptoms, emphasizing the therapy’s potential to enhance quality of life.
Desmoid tumors, while non-metastatic, can cause severe pain, functional impairment, and life-threatening complications, making effective treatment essential. The integration of clinical endpoints with patient-reported data reflects a growing trend in patient-centered drug development, aligning with regulatory expectations and modern clinical trial methodologies.
Advancing Regulatory Pathways and Oncology Innovation
The NDA submission represents a critical regulatory milestone for Immunome, signaling its transition toward potential commercialization of a late-stage oncology asset. The company plans to present detailed Phase 3 data at the 2026 American Society of Clinical Oncology (ASCO) Annual Meeting, further strengthening the clinical evidence base for varegacestat.
From a GxP perspective, the RINGSIDE trial adhered to Good Clinical Practice (GCP) standards, ensuring data integrity, patient safety, and regulatory compliance throughout the study. The submission also highlights the increasing importance of precision oncology and targeted therapies in addressing rare and difficult-to-treat conditions. As regulatory review progresses, varegacestat could become a transformative treatment option for desmoid tumor patients, offering a convenient oral alternative with strong efficacy and safety outcomes. This development reinforces Immunome’s position as an innovator in targeted cancer therapies, driving forward next-generation solutions that address unmet medical needs and improve patient outcomes globally.
Source: Immunome press release
