Study of Pembrolizumab (MK-3475) Plus Enzalutamide Versus Placebo Plus Enzalutamide in Participants With Metastatic Castration-resistant Prostate Cancer (mCRPC) (MK-3475-641/KEYNOTE-641)
Last updated:
Last updated
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2026-07-18
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A PHASE 3, RANDOMIZED, DOUBLE-BLIND TRIAL OF PEMBROLIZUMAB (MK-3475) PLUS ENZALUTAMIDE VERSUS PLACEBO PLUS ENZALUTAMIDE IN PARTICIPANTS WITH METASTATIC CASTRATION-RESISTANT PROSTATE CANCER (MCRPC) (KEYNOTE-641)
Intervention/treatment:
Intervention/treatment
Name given to the drug used in the clinical trial. This may be a code name, a chemical name of the active ingredient, a non-proprietary name or brand name.
KEYTRUDA [MK-3475 (PEMBROLIZUMAB)]
Medical condition:
Medical condition
The disease or condition that's being studied in the clinical trial.
PROSTATE CANCER METASTATIC CASTRATION RESISTANT
Protocol code:
Protocol Code
An alpha-numeric sequence generated by the sponsor that can vary in length. Used as a reference to help identify a specific clinical trial protocol. Formerly referred to as 'protocol number'.
MK-3475-641
Control number:
Control number
A unique 6-digit identification number Health Canada assigns to each clinical trial application.
227904
Status:
Trial Status
The status for the clinical trial as a whole. Note that the status for each site may be different and should always be confirmed with the clinical trial sponsor. Health Canada uses information provided by the sponsor to an international clinical trial registry to determine status values for each clinical trial. Status values on the portal can include:
• Not yet recruiting - Participants are not yet being recruited or enrolled at any site. • Recruiting - Participants are currently being recruited. • Active, not recruiting - The clinical trial is ongoing but new participants are not currently being recruited or enrolled. • On hold - The clinical trial has been temporarily stopped, but it may start again. • Closed - The clinical trial has either ended normally and participants are no longer being examined or treated, or it has stopped early and will not start again. • Unknown - The status of the clinical trial has not been verified in the registry in the last 2 years. Please contact the sponsor. • No match, ongoing - Please contact sponsor for status information. • Other - Please contact sponsor for status information.
Closed
Approved:
Approved
The date that the clinical trial has been determined to meet Health Canada’s regulatory requirements. For drug clinical trials, this means that a no objection letter or an authorization was issued.
June 20, 2019
Date Completed:
Date completed
The date of the last participant’s last visit in the global study. The completion date may be actual or estimated, depending what was provided to the registry. Estimated completion dates may be in the past or future.
Trial phase:
Trial phase
The stage of a clinical trial, based on factors such as the objectives of the trial and number of participants. Phase data displayed in the portal is taken from international registry data.
For more information see "Phases of drug trials" on the Definitions webpage
This is an external link. The information is not authorized by the Government of Canada.
Eligibility
Eligibility
The characteristics people must have or the requirements they must meet to participate in the clinical trial. Eligibility criteria include both inclusion criteria (must have for a person to participate) and exclusion criteria (prevent a person from participating).
Review the exact criteria from the registry or the sponsor before making a decision to participate. The following values may be available on the portal:
Sex: an eligibility criteria based on biological characteristics. Information in the portal is based on available data and will default to 'all' when no other data is available.
Age: The age a person must be to participate in the clinical trial.
Accepts Healthy Volunteers: People who do not have the disease or condition can participate in the clinical trial.
Sex:
MALE
Age
18 Years and older
Accepts healthy volunteers:
No
Contacts and locations
Contact
Contact
Information for an individual or organisation that can respond to questions about this clinical trial. This information comes from the international registry.
Name
Senior Vice President, Global Clinical Development
The sponsor conducts the clinical trial and is responsible for every aspect. For example this could be a company, a university or an individual researcher.
MERCK CANADA INC
Locations
British Columbia
BC Cancer Victoria-Clinical Trials Unit ( Site 0111)
Victoria, British Columbia, V8R 6V5
Ontario
Grand River Hospital ( Site 0120)
Kitchener, Ontario, N2G 1G3
Hamilton Health Sciences-Juravinski Cancer Centre ( Site 0116)
Hamilton, Ontario, L8V 5C2
Health Sciences North ( Site 0122)
Greater Sudbury, Ontario, P3E 5J1
Lakeridge Health ( Site 0117)
Oshawa, Ontario, L1G 2B9
Princess Margaret Cancer Centre ( Site 0107)
Toronto, Ontario, M5G 2M9
Sunnybrook Research Institute ( Site 0108)
Toronto, Ontario, M4N 3M5
Quebec
Centre Hospitalier de l Universite de Montreal - CHUM ( Site 0106)
Montreal, Quebec, H2X 3E4
Centre intégré de cancérologie du CHU de Québec Université Laval, Hôpital de l'Enfant-Jésus ( Site 0103)
Québec, Quebec, G1J 1Z4
CISSS de la Monteregie-Centre ( Site 0119)
Greenfield Park, Quebec, J4V 2H1
CIUSSS de l Estrie - CHUS - Centre Hosp. Univ. Sherbrooke ( Site 0105)
Sherbrooke, Quebec, J1H 5N4
CIUSSS du Bas Saint Laurent - Hopital Regional de Rimouski ( Site 0102)
