First Patient Dosed in MODeFIRe-1 Ph 2 Study of MRT-2359 + Apalutamide in Patients with AR Mutation-Positive Metastatic CRPC

“Dosing the first patient in MODeFIRe-1 is an important step in advancing MRT-2359 as a potential therapy for patients with mCRPC with AR mutations, a population with limited therapeutic options,” said Filip Janku, M.D., Ph.D., Chief Medical Officer of Monte Rosa Therapeutics. “This study builds on the encouraging results we observed in our Phase 1/2 study of MRT-2359 in combination with enzalutamide. As we disclosed previously, in that study of heavily pretreated, advanced CRPC patients – including those who had progressed on prior second-generation AR inhibitors, chemotherapy, and radioligand therapy – 5 of 5 patients with AR mutations demonstrated a PSA response, with a 100% disease control rate and two RECIST responses. MODeFIRe-1 pairs MRT-2359 with apalutamide using a design intended to efficiently further evaluate and potentially confirm clinical activity in this population. We believe this study can position MRT-2359 for advancement into registrational development if the data continue to support our earlier results, with the potential to also extend clinical benefit to additional AR-driven patient populations including patients without prior second-generation AR inhibitors, as well as into combinations with radioligand therapies independent of AR status.”