Immunome announced that it will seek approval from the U.S. Food and Drug Administration (FDA) for its investigational drug varegacestat following positive results in a Phase III clinical trial involving patients with progressing desmoid tumors.
The RINGSIDE trial, which tested varegacestat—an oral, once-daily gamma secretase inhibitor—showed an 84% reduction in the risk of disease progression or death compared to placebo. The drug achieved a 56% objective response rate versus 9% for placebo and also demonstrated significant reductions in tumor volume and pain intensity, meeting all key secondary endpoints, according to Immunome.
The company reported that the safety profile of varegacestat was manageable, with diarrhea, fatigue, and rash being the most common side effects; most were classified as mild or moderate.
Based on these findings, Immunome plans to submit a new drug application to the FDA for varegacestat in this indication during the second quarter of 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 Clay Siegall, CEO of Immunome.
Desmoid tumors are aggressive but non-metastatic soft tissue malignancies known for their tendency to recur. They can cause significant pain, deformity, and sometimes life-threatening organ damage. In the United States each year, between 1,000 and 1,650 people are diagnosed with desmoid tumors.
In November 2023, SpringWorks Therapeutics’ Ogsiveo became the first approved treatment for adults with desmoid tumors after showing favorable outcomes in its own Phase III DeFi trial. Ogsiveo’s study showed a 71% reduction in risk of disease progression compared to placebo. The median progression-free survival was not reached for those receiving Ogsiveo while it was 15.1 months for those on placebo. The confirmed objective response rates were 41% for Ogsiveo versus 8% for placebo.
Commenting on Immunome’s recent results, Mrinal Gounder—a sarcoma medical oncologist at Memorial Sloan Kettering Cancer Center and primary investigator of RINGSIDE—said: “These findings elevate the role of GSIs and confirm varegacestat could become standard of care in the treatment of desmoid tumors.”
