• Varegacestat treatment resulted in statistically significant improvements in primary and all key secondary efficacy endpoints
• Varegacestat demonstrated statistically significant improvement in worst pain intensity at week 12, with a clinically significant difference observed as early as the first evaluation at week 4
• Progression-free survival benefit was consistent across prespecified patient subgroups, including tumor location, baseline tumor size, patient age and prior systemic desmoid tumor therapy
• New Drug Application (NDA) for varegacestat submitted to the U.S. Food and Drug Administration (FDA) in April 2026, with Marketing Authorization Application (MAA) submission to the European Medicines Agency (EMA) planned by the end of 2026

Immunome, Inc. (Nasdaq: IMNM), a biotechnology company committed to developing first-in-class and best-in-class targeted cancer therapies, today announced detailed efficacy and safety results from RINGSIDE, the global, randomized, double-blind, placebo-controlled Phase 3 trial of varegacestat in patients with progressing desmoid tumors. The data are being presented today in an oral abstract session at the 2026 American Society of Clinical Oncology (ASCO) Annual Meeting in Chicago. Immunome submitted an NDA for varegacestat to the FDA in April 2026.

“Desmoid tumors can be locally aggressive, painful and unpredictable, creating a high disease burden for patients and a continued need for new treatment options,” said Mrinal M. Gounder, M.D., sarcoma medical oncologist and drug development specialist at Memorial Sloan Kettering Cancer Center, and the RINGSIDE primary investigator who is presenting the data. “The RINGSIDE data show a compelling progression-free survival benefit with varegacestat that is consistent across relevant patient subgroups, complemented by a high response rate and reduction in tumor volume. The data also show a rapid, clinically meaningful reduction in worst pain intensity, which is an important element for patients. These findings confirm varegacestat could become standard of care in the treatment of desmoid tumors.”

“The detailed RINGSIDE data presented at ASCO reinforce varegacestat’s differentiated efficacy and manageable safety profile,” said Clay Siegall, Ph.D., President and Chief Executive Officer of Immunome. “The depth and consistency of benefit observed across RINGSIDE point to varegacestat’s potential to deliver a meaningful advance for patients with desmoid tumors. These results form the basis for the NDA we submitted in April 2026 and the planned MAA submission for Europe.”

RINGSIDE Key Clinical Data Presented at 2026 ASCO Meeting

As previously reported, the RINGSIDE trial met its primary endpoint and all key secondary endpoints. Varegacestat demonstrated a statistically significant and clinically meaningful improvement in progression-free survival (PFS) vs. placebo, with an 84% reduction in the risk of disease progression or death (hazard ratio [HR] = 0.16, 95% confidence interval [CI]: 0.071, 0.375; p<0.0001). The PFS benefit observed with varegacestat vs. placebo was consistent across key subgroups, including tumor location, baseline tumor size, patient age and prior systemic desmoid tumor therapy.

As previously reported, 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. Among responders treated with varegacestat, median time to response was 8.2 months (range: 2.6–28.0 months) vs. 16.7 months (range: 8.1–30.2 months) for responders receiving placebo.

Varegacestat achieved a statistically significant improvement in change in worst pain intensity score at week 12, as assessed with the Gounder/Desmoid Tumor Research Foundation Desmoid Tumor Symptom/Impact scale. At week 12, patients treated with varegacestat experienced a mean change from baseline of -2.24 (standard error [SE]: 0.27) compared with +0.18 (SE: 0.27) for patients receiving placebo, for a treatment difference of -2.42 (SE: 0.37; p<0.0001). A clinically significant difference of more than 2 points was observed as early as the first evaluation at week 4.

Varegacestat achieved a statistically significant improvement in change in tumor volume at week 24, as assessed by blinded independent central review. At week 24, patients treated with varegacestat had a mean change from baseline of -109.6 (SE: 40.64) compared with +122.8 (SE: 42.72) for patients receiving placebo, for a treatment difference of -232.4 (SE: 57.39; p<0.0001). In a previously reported exploratory analysis, varegacestat demonstrated a median best change in tumor volume of -83% vs. +11% with placebo, also as assessed by blinded independent central review.

Varegacestat was generally well tolerated, with a manageable safety profile consistent with the gamma secretase inhibitor class. The most common adverse events for participants in the treatment arm as opposed to the placebo arm were diarrhea (82% vs. 27%), fatigue (44% vs. 23%), rash (43% vs. 12%), nausea (35% vs. 26%) and cough (34% vs. 5%). Most (95%) adverse events were grade 1 or 2. Among premenopausal women receiving varegacestat, 20 of 36 (56%) had ovarian toxicity adverse events, which resolved in 11 women (55%), and there were no discontinuations due to ovarian toxicity. Dose reductions due to treatment-emergent adverse events occurred in 80% of patients treated with varegacestat vs. 9% with placebo. Treatment discontinuations due to adverse events occurred in 20% of patients treated with varegacestat vs. 7% with placebo. The median exposure was 20.3 months for patients receiving varegacestat vs. 11.1 months for placebo.

Oral Presentation Details

The slides from Dr. Gounder’s oral presentation will be available on the Immunome website in the “Presentations” page of the Investor Relations section.

Financial Disclosure

Dr. Gounder has financial interests related to Immunome.

About the RINGSIDE Trial

The global, randomized, double-blind, placebo-controlled Phase 3 RINGSIDE trial (ClinicalTrials.gov Identifier: 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, representing the largest randomized study in this population. The primary endpoint of the trial was progression-free survival as assessed by blinded independent central review. Statistically controlled secondary endpoints were confirmed 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 at week 12 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 submitted an NDA to the FDA for varegacestat in April 2026 and plans to submit a Marketing Authorization Application to the European Medicines Agency for varegacestat by the end of 2026.

About Immunome, Inc.

Immunome is a clinical-stage targeted oncology company committed to developing first-in-class and best-in-class targeted cancer therapies. We are advancing an innovative portfolio of therapeutics, supported by a leadership team with deep experience in the design, development, and commercialization of cutting-edge therapies, including antibody-drug conjugates. Our pipeline includes varegacestat, an investigational gamma secretase inhibitor for which an NDA has been submitted to the U.S. FDA; IM-1021, a clinical-stage ROR1 ADC; IM-3050, an IND-cleared FAP-targeted radiotherapy; and IM-1617, an IND-cleared solid tumor ADC. We are also advancing a broad portfolio of early-stage ADCs pursuing undisclosed solid tumor targets.

Cautionary Statement Regarding Forward-Looking Statements

Statements in this press release that are not purely historical in nature are “forward-looking statements” within the meaning of the Private Securities Litigation Reform Act of 1995. We use words such as “advance,” “anticipate,” “if warranted,” “potential,” “plan,” “expect,” and similar expressions to identify these forward-looking statements. These forward-looking statements include statements regarding: Immunome’s expected timing for submitting an MAA to the EMA by the end of 2026; the potential for varegacestat to become an important treatment option; Immunome’s efforts to bring medicine to patients; the potential of Immunome’s targeted oncology therapies to be first-in-class or best-in-class therapies; and other statements regarding management’s intentions, plans, beliefs, expectations or forecasts for the future. These forward-looking statements are based on Immunome’s current expectations and involve assumptions that may never materialize or may prove to be incorrect; consequently, actual results may differ materially from those expressed or implied in the statements due to a number of factors, including the risk that initial clinical results may not be indicative of subsequent results; the risk that Immunome’s NDA submission for varegacestat is delayed based on regulatory feedback or otherwise, and that regulatory approvals for Immunome’s programs and product candidates are not obtained, are delayed or are subject to unanticipated conditions, including the risk that the results of Immunome’s trials for varegacestat may not be deemed sufficient by the FDA to serve as the basis for regulatory approval of varegacestat; the risks associated with the potential safety and other complications from varegacestat; the labelling for varegacestat, if approved; the scope, progress and expansion of developing and commercializing varegacestat, if approved; the size and growth of the market for varegacestat and the rate and degree of its market acceptance; the risk that Immunome will not be able to realize the benefits of its strategic transactions; uncertainties related to Immunome’s capital requirements and Immunome’s expected cash runway; Immunome’s ability to grow and advance its pipeline and successfully execute on its business plan; and other risks and uncertainties included under the caption “Risk Factors” in Immunome’s Quarterly Report on Form 10-Q for the quarter ended March 31, 2026, filed with the Securities and Exchange Commission on May 12, 2026. These documents can also be accessed on Immunome’s website at www.immunome.com by clicking on the link “Financials” under the “Investors” tab. The forward-looking statements included in this press release are made only as of the date hereof. Except as required by law, Immunome assumes no obligation and does not intend to update any forward-looking statements included in this press release.

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