Study of Pembrolizumab (MK-3475) Plus Docetaxel Versus Placebo Plus Docetaxel in Chemotherapy-naïve Metastatic Castration-resistant Prostate Cancer (mCRPC) (MK-3475-921/KEYNOTE-921)

Official Title

A Phase 3, Randomized, Double-blind Study of Pembrolizumab (MK-3475) Plus Docetaxel Plus Prednisone Versus Placebo Plus Docetaxel Plus Prednisone in Participants With Chemotherapy-naïve Metastatic Castration-Resistant Prostate Cancer (mCRPC) Who Have Progressed on a Next Generation Hormonal Agent (NHA) (KEYNOTE-921)

Summary:

The purpose of this study is to assess the efficacy and safety of the combination of pembrolizumab (MK-3475) and docetaxel in the treatment of men with metastatic castration-resistant prostate cancer (mCRPC) who have not received chemotherapy for mCRPC but have progressed on or are intolerant to Next Generation Hormonal Agent (NHA). There are two primary study hypotheses. Hypothesis 1: The combination of pembrolizumab plus docetaxel plus prednisone is superior to placebo plus docetaxel plus prednisone with respect to Overall Survival (OS). Hypothesis 2: The combination of pembrolizumab plus docetaxel plus prednisone is superior to placebo plus docetaxel plus prednisone with respect to Radiographic Progression-free Survival (rPFS) per Prostate Cancer Working Group (PCWG)-modified Response Evaluation Criteria in Solid Tumours Version 1.1 (RECIST 1.1) as assessed by blinded independent central review.

Trial Description

Primary Outcome:

• Overall Survival (OS)
• Radiographic Progression-free Survival (rPFS) Per Prostate Cancer Working Group (PCWG)-modified Response Evaluation Criteria in Solid Tumours Version 1.1 (RECIST 1.1) as Assessed by Blinded Independent Central Review

• Time to Initiation of the First Subsequent Anti-cancer Therapy or Death (TFST)
• Prostate-specific Antigen (PSA) Response Rate
• Objective Response Rate (ORR) Per Prostate Cancer Working Group (PCWG)-modified Response Evaluation Criteria in Solid Tumours Version 1.1 (RECIST 1.1) as Assessed by Blinded Independent Central Review
• Duration of Response (DOR) Per Prostate Cancer Working Group (PCWG)-modified Response Evaluation Criteria in Solid Tumours Version 1.1 (RECIST 1.1) as Assessed by Blinded Independent Central Review
• Time to Pain Progression (TTPP) as Assessed by Brief Pain Inventory-Short Form (BPI-SF) Item 3 ("Worst Pain in 24 Hours") and Opiate Analgesic Use (Analgesic Quantification Algorithm [AQA] Score)
• Time to First Symptomatic Skeletal-related Event (SSRE)
• Time to Prostate-specific Antigen (PSA) Progression
• Time to Radiographic Soft Tissue Progression Per Soft Tissue Rules of Prostate Cancer Working Group (PCWG)-modified Response Evaluation Criteria in Solid Tumours Version 1.1 (RECIST 1.1) as Assessed by Blinded Independent Central Review
• Number of Participants Who Experience an Adverse Event (AE)
• Number of Participants Who Discontinue Study Treatment Due to an Adverse Event (AE)

View this trial on ClinicalTrials.gov