A new clinical trial, MEVPRO-3, is set to begin enrolling participants to evaluate whether combining Mevrometostat (PF-06821497), an investigational drug, with Enzalutamide offers better outcomes than Enzalutamide alone for men with metastatic castration-sensitive prostate cancer (mCSPC) who have not previously received Androgen Receptor Pathway Inhibitors (ARPIs). This Phase 3, randomized, double-blind, placebo-controlled study aims to enroll approximately 900 men globally to assess the safety and efficacy of this combination therapy.The trial targets men with histologically confirmed prostate adenocarcinoma, metastatic disease in bone or soft tissue, and progressive disease despite medical or surgical castration, with testosterone levels at or below 50 ng/dL.

Participants will be randomly assigned in a 1:1 ratio to receive either Mevrometostat (875 mg twice daily with food) plus Enzalutamide (160 mg once daily) or a placebo plus Enzalutamide.  The primary measure of success is radiographic progression-free survival (rPFS), which tracks how long the treatment delays disease progression based on imaging.
Mevrometostat is a selective inhibitor of EZH2, a protein linked to prostate cancer progression and resistance to hormone therapies like Enzalutamide. By blocking abnormal EZH2 activity, Mevrometostat may help delay resistance to hormone therapy and slow cancer growth.  The trial builds on earlier studies, such as a Phase 1/2 trial (NCT03460977) in metastatic castration-resistant prostate cancer (mCRPC), which showed that Mevrometostat plus Enzalutamide extended median rPFS to 14.3 months compared to 6.2 months for Enzalutamide alone in patients previously treated with Abiraterone. That study also reported manageable side effects, including diarrhea, anemia, and fatigue, with no treatment-related deaths.Recruitment for MEVPRO-3 is preparing to start, with study sites across multiple countries.

Clinical trial.