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Monte Rosa Therapeutics Presents Updated Clinical Data from Phase 1/2 Study of MRT-2359 in Combination with Enzalutamide in Heavily Pretreated Metastatic Castration-Resistant Prostate Cancer Patients at ASCO Genitourinary Cancers Symposium (ASCO GU)
In mCRPC patients with androgen receptor (AR) mutations, treatment with MRT-2359 in combination with enzalutamide led to a 100% PSA response rate (5 of 5
About this update from Monte Rosa Therapeutics, Inc.
[{"type":"text","content":"In mCRPC patients with androgen receptor (AR) mutations, treatment with MRT-2359 in combination with enzalutamide led to a 100% PSA response rate (5 of 5 patients) and a 100% disease control rate, including 2 patients with RECIST partial responses and 3 with stable disease, all showing reduction in size of target lesions Across all 15 evaluable patients, the overall RECIST disease control rate was 67%, and 10 of 15 patients showed tumor size reductions of target lesions Combination of MRT-2359 and enzalutamide was generally well-tolerated with primarily Grade 1-2 adverse events (AEs); no treatment discontinuations due to AEs Company plans to initiate a new, signal-confirming Phase 2 study of MRT-2359 targeting AR mutant patients in Q3 2026 Poster presentation on February 26 at 11:30 AM PST BOSTON, Feb. 24, 2026 (GLOBE NEWSWIRE) -- Monte Rosa Therapeutics, Inc. (Nasdaq: GLUE), a clinical-stage biotechnology company developing novel molecular glue degrader (MGD)-based medicines, today announced updated, positive clinical data from an ongoing Phase 1/2 clinical study evaluating MRT-2359 in combination with enzalutamide in heavily pretreated patients with metastatic castration-resistant prostate cancer (mCRPC). The data, being presented at the 2026 ASCO GU Symposium in San Francisco, CA, build on data released by the company in December 2025. MRT-2359 is an investigational, orally bioavailable, GSPT1-directed MGD discovered and developed by Monte Rosa. “These data bolster the promising results we shared in December, continuing to reinforce MRT-2359's potential in mCRPC patients with AR mutations, a population with limited therapeutic options,” said Filip Janku, M.D., Ph.D., Chief Medical Officer of Monte Rosa Therapeutics. “Strikingly, in this updated dataset, 5 of 5 patients with AR mutations demonstrated a PSA response, including 2 PSA90 responses and 3 PSA50 responses. Based on the encouraging efficacy data and favorable safety profile observed to date, we plan to initiate a new Phase 2 study this year to evaluate MRT-2359 in combination with a second-generation AR-inhibitor in mCRPC patients with AR mutations. This Phase 2 study is designed to confirm MRT-2359’s clinical activity and position the program for advancement into registrational studies.” The ongoing Phase 1/2 study evaluated 0.5 mg and 0.75 mg of MRT-2359 administere...