On December 15, 2025 Immunome, Inc. (Nasdaq: IMNM), a biotechnology company committed to developing first-in-class and best-in-class targeted cancer therapies, reported positive topline results from the global pivotal Phase 3 RINGSIDE trial of varegacestat, an investigational, oral, once-daily gamma secretase inhibitor (GSI), in patients with progressing desmoid tumors.

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The trial met its primary endpoint of improving progression-free survival, demonstrating a statistically significant and clinically meaningful improvement vs. placebo, with an 84% reduction in the risk of disease progression or death (hazard ratio (HR) = 0.16, 95% CI: 0.071, 0.375; p<0.0001). The confirmed objective response rate (ORR) based on RECIST v1.1 was 56% with varegacestat vs. 9% with placebo (p<0.0001), as assessed by blinded independent central review. In an exploratory analysis, varegacestat demonstrated a median best change in tumor volume of -83% vs. +11% with placebo, as assessed by blinded independent central review. In addition, the trial met all key secondary endpoints, with varegacestat achieving statistically significant improvements vs. placebo in landmark tumor volume reduction and worst pain intensity.

Varegacestat was generally well tolerated, with a manageable safety profile consistent with the GSI class. The most common adverse events for participants in the treatment arm were diarrhea (82%), fatigue (44%), rash (43%), nausea (35%) and cough (34%). Most events were grade 1 or 2.

Based on these data, Immunome plans to submit a New Drug Application to the U.S. Food and Drug Administration in Q2 2026.

"RINGSIDE is the largest and most comprehensive clinical trial conducted to date in patients with desmoid tumors, and the topline results represent the highest objective response rate observed in a randomized clinical trial in this patient population," said Immunome’s CEO Clay Siegall, Ph.D. "These findings demonstrate the potential of varegacestat to offer best-in-class results in a convenient, once-daily, oral medicine that may help patients reclaim their lives."

"Desmoid tumors can have a devastating physical and emotional impact on patients given their unpredictable nature and the limitations of current treatment options," said Mrinal M. Gounder, M.D., sarcoma medical oncologist and drug development specialist at Memorial Sloan Kettering Cancer Center, and RINGSIDE primary investigator. "The progression-free survival benefit, high response rate and reduction in tumor volume with varegacestat in the RINGSIDE trial are striking. These findings elevate the role of GSIs and confirm varegacestat could become standard of care in the treatment of desmoid tumors."

Dr. Siegall added, "The RINGSIDE results represent a major milestone for Immunome as we advance our emerging pipeline of targeted oncology therapies that have exceptional potential to meaningfully improve the lives of patients."

Immunome plans to share additional data from the RINGSIDE trial at an upcoming major medical conference.

Webcast, Presentation Slides and Conference Call Information

Immunome will host a webcast and conference call on Monday, December 15, 2025, at 8:30 a.m. ET / 5:30 a.m. PT to discuss the Phase 3 RINGSIDE trial topline results. A live webcast, which will include presentation slides, can be accessed using this link or by visiting the Events and Presentations section of the Immunome website at View Source The conference call can be accessed by clicking on the call link and completing the online registration form, which will enable the selection of a dial-in number or callback from the system. A live question-and-answer session will follow the prepared remarks. Participants wishing to ask a question must do so via the conference call; the webcast will be listen-only. After the live webcast, the event will remain archived on the Immunome website for 90 days.

About the RINGSIDE Trial

The global, randomized, double-blind, placebo-controlled Phase 3 RINGSIDE trial (NCT04871282) evaluated the efficacy and safety of varegacestat in patients with progressing desmoid tumors. A total of 156 patients were randomized to receive varegacestat 1.2 mg daily or placebo until disease progression or death. The primary endpoint of the trial was progression-free survival as assessed by blinded independent central review. Statistically controlled secondary endpoints were ORR using RECIST v1.1 and change in tumor volume at week 24, both determined by blinded independent central review, as well as change in pain intensity as determined using a patient reported outcome instrument. Additional secondary endpoints included duration of response, best reduction in tumor volume, patient-reported outcomes, and safety and tolerability. RINGSIDE includes an open-label extension phase, which is ongoing.

About Desmoid Tumors

Desmoid tumors (also known as aggressive fibromatosis or desmoid-type fibromatosis) are aggressive non-metastatic soft tissue tumors that are prone to recurrence. Approximately 1,000-1,650 people are diagnosed with desmoid tumors each year in the United States, and there are approximately 10,000-11,000 actively managed patients. Those affected face debilitating pain, deformity and, in some cases, life-threatening organ damage. The chronic pain and physical limitations associated with desmoid tumors lead to a high clinical burden and impaired quality of life. Although desmoid tumors are not considered cancerous, they often require systemic treatment to prevent permanent disability and alleviate disease burden.

About Varegacestat

Varegacestat (formerly AL102) is an investigational, oral, once-daily gamma secretase inhibitor. In December 2025, Immunome reported positive topline results for the Phase 3 RINGSIDE trial of varegacestat in adults with progressing desmoid tumors. Immunome plans to submit a New Drug Application for varegacestat to the U.S. Food and Drug Administration in Q2 2026.

(Press release, Immunome, DEC 15, 2025, View Source [SID1234661423])