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Mevrometostat plus enzalutamide versus enzalutamide alone for men with metastatic castration‑sensitive prostate cancer who are ARPI‑naïve

A Phase 3, Randomized, Double-Blind, Placebo-Controlled Study of Mevrometostat (PF-06821497) With Enzalutamide in Metastatic Castration-Sensitive Prostate Cancer (MEVPRO-3)

Phase 3 Interventional Pfizer · NCT07028853

This trial will test whether adding the investigational drug mevrometostat to enzalutamide helps men with metastatic castration‑sensitive prostate cancer who have not received androgen receptor pathway inhibitors or chemotherapy.

Quick facts

PhasePhase 3
Study typeInterventional
Enrollment1000 (estimated)
Ages18 Years and up
SexMale
SponsorPfizer Industry-sponsored
Drugs / interventionschemotherapy
Locations300 sites (Huntsville, Alabama and 299 other locations)
Trial IDNCT07028853 on ClinicalTrials.gov

What this trial studies

This global, multicenter, randomized, double‑blind, placebo‑controlled Phase 3 trial enrolls men with metastatic castration‑sensitive prostate cancer who are ARPI‑naïve and have not received chemotherapy in the mCSPC setting. Participants are randomized 1:1 to receive mevrometostat (PF‑06821497) plus enzalutamide or placebo plus enzalutamide alongside standard androgen‑deprivation therapy as needed. The study includes screening, treatment, safety follow‑up, and long‑term follow‑up visits, with prior short‑term ADT (up to 3 months) allowed if there is no radiographic progression or rising PSA before Day 1. Efficacy and safety endpoints will compare progression and adverse events between the combination and control arms.

Who should consider this trial

Good fit: Men aged 18 or older with histologically confirmed prostate adenocarcinoma, documented metastatic castration‑sensitive disease, ECOG 0–1, who are ARPI‑naïve and have not had chemotherapy for mCSPC (prior short‑term ADT up to 3 months allowed) are the intended participants.

Not a fit: Patients with small‑cell features, prior AR pathway inhibitor or chemotherapy in the mCSPC setting, clinically significant cardiovascular disease, known or suspected brain metastases, or poor performance status (ECOG >1) are unlikely to be eligible or to benefit.

Why it matters

Potential benefit: If successful, the combination could delay disease progression and extend time without needing additional systemic therapy compared with enzalutamide alone.

How similar studies have performed: Preclinical work and early‑phase studies of EZH2 inhibitors combined with androgen‑receptor targeted agents have shown promise, but definitive benefit in Phase 3 settings has not yet been established.

Eligibility criteria

Show full inclusion / exclusion criteria 
Inclusion Criteria

* Male participants aged ≥18 years (or the minimum age of consent in accordance with local regulations) at screening.
* Histologically or cytologically confirmed adenocarcinoma of the prostate without small cell features.
* Metastatic prostate cancer documented by positive bone scan (for bone disease) or metastatic lesion(s) on CT or MRI (for soft tissue/visceral disease).
* Resolution of acute effects of any prior therapy to either baseline severity or CTCAE Grade ≤1 (except for AEs which do not constitute a safety risk in the investigator's judgement).
* Participants must have ECOG PS 0 or 1.

Exclusion Criteria

* Any medical or psychiatric condition including recent (within the past year) or active suicidal ideation/behavior or laboratory abnormality that may increase the risk of study participation or, in the investigator's judgment, make the participant inappropriate for the study.
* Clinically significant cardiovascular disease.
* Known or suspected brain metastasis or active leptomeningeal disease.
* Participants must be treatment naïve at the mCSPC stage, eg, participants cannot have received any cytotoxic chemotherapy with the following exceptions: Treatment with first-generation antiandrogen (ADT) agents is allowed for mCSPC.
* Previous administration with an investigational product (drug or vaccine) within 30 days.
* Use of 5-alpha reductase inhibitors is prohibited within 28 days of randomization.
* Prior surgery from which the participant has not fully recovered at least 28 days prior to randomization
* Current use or anticipated need for drugs that are known strong CYP3A4/5 inhibitors and inducers (with exception of enzalutamide as part of this study).
* Inadequate organ function.

Where this trial is running

Huntsville, Alabama and 299 other locations

+250 more sites — see ClinicalTrials.gov for the full list.

Study contacts

How to participate

  1. Review the eligibility criteria above with your treating physician.
  2. Visit the official trial page on ClinicalTrials.gov for the most current contact information and recruitment status.
  3. Contact the listed study coordinator or principal investigator to request pre-screening. Pre-screening is free and never obligates you to enroll.
View on ClinicalTrials.gov → Find more trials like this →
Conditions Metastatic Castration Sensitive Prostate CancerHormone Sensitive Prostate CancerProstate CancerCancer of the ProstateMevrometostatMetastatic castration sensitive prostate cancerPF-06821497EZH2
Last reviewed 2026-06-13 by the Find a Trial editorial team. Information on this page is for educational purposes and is not medical advice. Always consult qualified healthcare professionals about clinical trial participation.