Monte Rosa Secures J&J Supply for Phase 2 MRT-2359/Apalutamide mCRPC Trial
Monte Rosa secured a supply agreement with Johnson & Johnson to support a Phase 2 trial of MRT-2359 combined with apalutamide in AR-mutant metastatic castration-resistant prostate cancer patients. The study will enroll up to 25 patients and is slated to start in the third quarter of 2026.
1. Supply Agreement Details
Monte Rosa Therapeutics has entered a clinical supply agreement with Johnson & Johnson under which J&J will provide ERLEADA (apalutamide) for a planned Phase 2 study in AR-mutant mCRPC. Monte Rosa will conduct and sponsor the trial, integrating ERLEADA into the MRT-2359 combination regimen.
2. Phase 2 Trial Design
The Phase 2 study, set to start in Q3 2026, will enroll up to 25 metastatic castration-resistant prostate cancer patients harboring androgen receptor mutations. It will assess PSA and RECIST responses, duration of response, progression-free survival, radiographic progression-free survival and safety, with potential expansion into AR inhibitor-naïve cohorts.
3. MRT-2359 Mechanism and Early Data
MRT-2359 is an orally bioavailable, GSPT1-directed molecular glue degrader that selectively disrupts translation termination factors to reduce oncoprotein levels including AR, MYC and Cyclin D1-E2F. In an ongoing Phase 1/2 study combined with enzalutamide, it has shown early clinical responses in heavily pretreated patients.
4. Strategic Outlook
Positive Phase 2 results could position MRT-2359 for registrational trials and establish a new therapy for mCRPC patients with limited options. The agreement underscores Monte Rosa’s strategy to leverage collaborations and expand its MGD pipeline into late-stage development.