This Study Will Explore Whether a Combination of the Investigational Drug Mevrometostat (PF-06821497) and Enzalutamide Will Work Better Than Taking Enzalutamide Alone in Participants With mCSPC Who Are ARPI naïve.

Pfizer

Status and phase: Enrolling; Phase 3

Conditions: Metastatic Castration Sensitive Prostate Cancer (mCSPC); Hormone Sensitive Prostate Cancer; Prostate Cancer; Cancer of the Prostate

Treatments: Drug: Enzalutamide; Drug: Mevrometostat; Drug: Placebo

Study type: Interventional

Funder types: Industry

Identifiers

NCT07028853

2024-519369-24-00 (Registry Identifier)

C2321008

MEVPRO-3 (Other Identifier)

Details and patient eligibility

About

This study will explore whether a combination of the investigational drug mevrometostat (PF-06821497) and enzalutamide will work better than taking enzalutamide alone in participants with mCSPC who are ARPI naïve and have not yet received chemotherapy in the mCSPC setting.

Full description

This is a global, multicenter, randomized, double-blind, placebo-controlled Phase 3 study evaluating mevrometostat in combination with enzalutamide versus placebo in combination with enzalutamide in participants with mCSPC who have not received systemic anticancer treatments with the exception of androgen-deprivation therapy (ADT) and first-generation antiandrogen agents. Prior therapy with up to 3 months of ADT (chemical or surgical) is allowed, with no radiographic evidence of disease progression or rising PSA levels prior to Day 1.

This study consists of a Screening Phase, Randomization, Treatment Phase, Safety Follow-up, and Long-Term Follow-up. Participants will be randomized on a 1:1 basis to receive (Arm A) mevrometostat (PF-06821497) in combination with enzalutamide, or (Arm B) placebo in combination with enzalutamide.

Enrollment: 1,000 estimated patients

Sex: Male

Ages: 18+ years old

Volunteers: No Healthy Volunteers

Inclusion and 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.
• 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.

Trial design

Primary purpose: Treatment

Allocation: Randomized

Interventional model: Parallel Assignment

Masking: Quadruple Blind

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1,000 participants in 2 patient groups

Arm A

Experimental group

Description:

Participants will receive mevrometostat/PF-06821497 (875 mg) BID (twice daily) + enzalutamide 160 mg QD (once daily)

Treatment:

Drug: Enzalutamide

Drug: Mevrometostat

Arm B

Active Comparator group

Description:

Participants will receive Placebo BID (twice daily) + enzalutamide 160 mg QD (once daily)

Treatment:

Drug: Placebo

Drug: Enzalutamide