Efficacy and Safety of Pembrolizumab (MK-3475) Plus Enzalutamide Plus Androgen Deprivation Therapy (ADT) Versus Placebo Plus Enzalutamide Plus ADT in Participants With Metastatic Hormone-Sensitive Prostate Cancer (mHSPC) (MK-3475-991/KEYNOTE-991)

Metastatic Hormone-Sensitive Prostate Cancer Clinical Trial

Official title:
A Phase 3, Randomized, Double-blind Trial of Pembrolizumab (MK-3475) Plus Enzalutamide Plus ADT Versus Placebo Plus Enzalutamide Plus ADT in Participants With Metastatic Hormone-Sensitive Prostate Cancer (mHSPC) (KEYNOTE-991)

Status Active, not recruiting

Clinical Trial Summary

This study will assess the efficacy and safety of pembrolizumab plus enzalutamide plus Androgen Deprivation Therapy (ADT) versus placebo plus enzalutamide plus ADT in participants with mHSPC. The primary hypothesis is that in participants with mHSPC, the combination of pembrolizumab plus enzalutamide plus ADT is superior to placebo plus enzalutamide plus ADT with respect to 1) radiographic progression-free survival (rPFS) per Prostate Cancer Working Group (PCWG)-modified Response Evaluation Criteria in Solid Tumors (RECIST) 1.1 as assessed by blinded independent central review (BICR) and 2) overall survival (OS). As of 19-JAN-2023, the study was unblinded and all study participants stopped ongoing treatment with pembrolizumab/placebo and will continue to receive Standard of Care treatment until meeting protocol-specified discontinuation criteria if deriving clinical benefit. Safety analysis will be performed at the end of the study; there will be no further analyses for efficacy and electronic patient-reported outcome (ePRO) endpoints collected from participants beyond the IA1 cutoff date. All study participants will stop ongoing treatment with pembrolizumab/placebo. Exceptions may be requested for study participants who, in the assessment of their study physician, are benefitting from the combination of enzalutamide and pembrolizumab, after consulting with the Sponsor. All other study participants should be discontinued from study and be offered standard of care (SOC) treatment as deemed necessary by the Investigator. If enzalutamide as SOC is not accessible off study to the participant, central sourcing may continue. As of Amendment 04, disease progression will no longer be centrally verified, participants will only be assessed locally. As of Amendment 4, Second Course treatment is not an option for participants. There are currently no participants in the Second Course Phase.

Clinical Trial Description

n/a

Study Design

Related Conditions & MeSH terms

Hypersensitivity
Metastatic Hormone-Sensitive Prostate Cancer
Prostatic Neoplasms

Clinical Trial Details

NCT number	NCT04191096
Study type	Interventional
Source	Merck Sharp & Dohme LLC
Contact
Status	Active, not recruiting
Phase	Phase 3
Start date	February 12, 2020
Completion date	February 2, 2026

View Details

See also
Status	Clinical Trial	Phase
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Active, not recruiting	`NCT00309985` - Androgen Ablation Therapy With or Without Chemotherapy in Treating Patients With Metastatic Prostate Cancer	Phase 3
Completed	`NCT03532217` - Neoantigen DNA Vaccine in Combination With Nivolumab/Ipilimumab and PROSTVAC in Metastatic Hormone-Sensitive Prostate Cancer	Phase 1
Active, not recruiting	`NCT05059236` - A Study to Learn How Well Darolutamide Administered Together With Androgen Deprivation Therapy (ADT) Works in Men With Metastatic Hormone-sensitive Prostate Cancer. Results Will be Compared With ADT Alone From a Previously Conducted Study.	Phase 2
Completed	`NCT02799602` - Darolutamide in Addition to Standard Androgen Deprivation Therapy and Docetaxel in Metastatic Hormone-Sensitive Prostate Cancer	Phase 3
Not yet recruiting	`NCT06134271` - Rezvilutamide Plus Abiraterone for Metastatic Hormone-sensitive Prostate Cancer	Phase 2
Active, not recruiting	`NCT04934722` - Efficacy and Safety of Pembrolizumab (MK-3475) Plus Enzalutamide Plus Androgen Deprivation Therapy (ADT) Versus Placebo Plus Enzalutamide Plus ADT in Participants With Metastatic Hormone-Sensitive Prostate Cancer (mHSPC) (MK-3475-991/KEYNOTE-991)-China Extension	Phase 3
Not yet recruiting	`NCT06334120` - An Observational Study to Learn More About the Safety of Darolutamide in Men With Prostate Cancer in Korea
Recruiting	`NCT05901649` - A Study for the Participants With Metastatic Hormone Sensitive Prostate Cancer (mHSPC) Treated With Androgen Deprivation Therapy (ADT) Plus Apalutamide or Enzalutamide
Withdrawn	`NCT03343977` - Toxicity & Pharmacokinetics of 2 & 3-weekly Docetaxel in Metastatic Hormone-Sensitive Prostate Cancer (mHSPC)	Phase 1/Phase 2
Active, not recruiting	`NCT03879122` - A Trial of Immunotherapy Strategies in Metastatic Hormone-sensitive Prostate Cancer	Phase 2/Phase 3

Clinical trials are conducted in a series of steps, called phases - each phase is designed to answer a separate research question.

Phase 1: Researchers test a new drug or treatment in a small group of people for the first time to evaluate its safety, determine a safe dosage range, and identify side effects.
Phase 2: The drug or treatment is given to a larger group of people to see if it is effective and to further evaluate its safety.
Phase 3: The drug or treatment is given to large groups of people to confirm its effectiveness, monitor side effects, compare it to commonly used treatments, and collect information that will allow the drug or treatment to be used safely.
Phase 4: Studies are done after the drug or treatment has been marketed to gather information on the drug's effect in various populations and any side effects associated with long-term use.