Trial · NCT03834493
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)
NCT03834493, Phase 3, Terminated, Merck Sharp & Dohme LLC; results first posted 2023-12-20
3 sourcestrials-2026-11-12-0.5.0
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ConductScience Library. 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). Trials, record NCT03834493. Release trials-2026-11-12-0.5.0, 12 Nov 2026. https://conductscience.org/library/trials/NCT03834493
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Trial
As registered on ClinicalTrials.gov, in the graph's capture of the registry.
- Title
- 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)
- NCT number
- NCT03834493
- Status
- Terminated
- Phases
- Phase 3
- Enrollment
- 1,244 participants, actual
- Lead sponsor
- Merck Sharp & Dohme LLC
- Conditions
- Prostatic Neoplasms
- Interventions
- Pembrolizumab, Enzalutamide, Placebo
- First posted
- 2019-02-08
- Last updated
- 2026-09-28
- Other registries' IDs
- eudract:2018-004117-40
- Results first posted
- 2023-12-20
Source ClinicalTrials.gov
Registered outcomes13
Each outcome the trial registered, primary first, in ClinicalTrials.gov's words.
| List | Outcome | Time frame | Description |
|---|---|---|---|
| Primary | Overall Survival (OS) | Up to 40 months (through database cut-off date of 12-Dec-2022) | OS was defined as the time from randomization to death due to any cause. The OS for all participants is presented. |
| Primary | Radiographic Progression-free Survival (rPFS) Per Prostate Cancer Working Group (PCWG)-Modified Response Evaluation Criteria in Solid Tumors Version 1.1 (RECIST 1.1) as Assessed by Blinded Independent Central Review | Up to 40 months (through database cut-off date of 12-Dec-2022) | rPFS was defined as the time from randomization to the first documented progressive disease (PD) per PCWG-modified RECIST 1.1 based on blinded independent central review or death due to any cause, whichever occurred first. The rPFS per PCWG-modified RECIST for all participants is presented. |
| Secondary | Time to Initiation of the First Subsequent Anti-cancer Therapy or Death (TFST) | Up to 40 months (through database cut-off date of 12-Dec-2022) | TFST was defined as time from randomization to initiation of the first subsequent anti-cancer therapy or death, whichever occurs first. The TFST for all participants is presented. |
| Secondary | Prostate-specific Antigen (PSA) Response Rate | Up to 40 months (through database cut-off date of 12-Dec-2022) | PSA response rate was defined as percentage of participants in the analysis population who have a negative change (decrease) in PSA level of ≥50% measured twice ≥3 weeks apart. The analysis was performed on participants who had baseline PSA measurements. |
| Secondary | Prostate-specific Antigen (PSA) Undetectable Rate | Up to 40 months (through database cut-off date of 12-Dec-2022) | PSA undetectable rate was defined as percentage of participants in the analysis population with PSA \<0.2 ng/mL during study treatment. The analysis was performed on participants who had baseline PSA measurements. |
| Secondary | Objective Response (OR) Per Prostate Cancer Working Group (PCWG)-Modified Response Evaluation Criteria in Solid Tumors Version 1.1 (RECIST 1.1) by as Assessed by Blinded Independent Central Review | Up to 40 months (through database cut-off date of 12-Dec-2022) | OR was defined as the percentage of participants with complete response (CR: disappearance of all target lesions per RECIST 1.1; and no evidence of disease (NED) on bone scan per PCWG) or partial response (PR: at least a 30% decrease in the sum of diameters of target lesions per RECIST 1.1; and non-progressive disease, non-evaluable \[NE\], or NED on bone scan or CR with non-progressive disease or NE bone scan per PCWG). |
| Secondary | Duration of Response (DOR) Per Prostate Cancer Working Group (PCWG)-Modified Response Evaluation Criteria in Solid Tumors Version 1.1 (RECIST 1.1) by as Assessed by Blinded Independent Central Review | Up to 40 months (through database cut-off date of 12-Dec-2022) | DOR was defined as the time from first documented evidence of complete response (CR) or partial response (PR) per PCWG and RECIST 1.1 criteria until progressive disease (PD) or death. PD per RECIST 1.1 was defined as at least a 20% increase in the sum of diameters of target lesions. In addition to the relative increase of 20%, the sum must also demonstrate an absolute increase of at least 5 mm. PD per PCWG was the appearance of ≥2 new bone lesions on bone scan, that have been confirmed to not represent tumor flare, and were persistent for ≥6 weeks. The DOR was calculated using the product-limit (Kaplan-Meier) method for censored data. If a participant had not progressed, the participant was censored at the date of last disease assessment. |
| Secondary | Time to Prostate-specific Antigen (PSA) Progression | Up to 40 months (through database cut-off date of 12-Dec-2022) | Time from randomization to PSA progression. PSA progression date is defined as the date of 1) ≥25% increase and ≥2 ng/mL above the nadir, confirmed by a second value ≥3 weeks later if there is PSA decline from baseline, or 2) ≥25% increase and ≥2 ng/mL increase from baseline beyond 12 weeks if there is no PSA decline from baseline. |
| Secondary | Time to Radiographic Soft Tissue Progression Per Soft Tissue Rules of Prostate Cancer Working Group (PCWG)-Modified Response Evaluation Criteria in Solid Tumors Version 1.1 (RECIST 1.1) by as Assessed by Blinded Independent Central Review | Up to 40 months (through database cut-off date of 12-Dec-2022) | Time from randomization to radiographic soft tissue progression per PCWG-modified RECIST 1.1 |
| Secondary | 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) | Up to 40 months (through database cut-off date of 12-Dec-2022) | Time from randomization to pain progression. In this study, pain progression was assessed by participant responses to Item 3 of the BPI-SF and participant AQA Scores which are both assessed by participants daily for 7 consecutive days. |
1 to 10 of 13Source ClinicalTrials.gov
See all 13 registered outcomesOutcomes13
Each outcome the trial posted results for, in ClinicalTrials.gov's words.
| Type | Outcome | Time frame | Population | Units | Measured as |
|---|---|---|---|---|---|
| PRIMARY | Overall Survival (OS) | Up to 40 months (through database cut-off date of 12-Dec-2022) | The efficacy analysis population consisted of all randomized participants. Participants were included in the treatment group to which they were randomized. | Months | MEDIAN |
| PRIMARY | Radiographic Progression-free Survival (rPFS) Per Prostate Cancer Working Group (PCWG)-Modified Response Evaluation Criteria in Solid Tumors Version 1.1 (RECIST 1.1) as Assessed by Blinded Independent Central Review | Up to 40 months (through database cut-off date of 12-Dec-2022) | The efficacy analysis population consisted of all randomized participants. Participants were included in the treatment group to which they were randomized. | Months | MEDIAN |
| SECONDARY | Time to Initiation of the First Subsequent Anti-cancer Therapy or Death (TFST) | Up to 40 months (through database cut-off date of 12-Dec-2022) | The efficacy analysis population consisted of all randomized participants. Participants were included in the treatment group to which they were randomized. | Months | MEDIAN |
| SECONDARY | Prostate-specific Antigen (PSA) Response Rate | Up to 40 months (through database cut-off date of 12-Dec-2022) | The efficacy analysis population consisted of all randomized participants in the intent to treat population, who had a PSA measurement at baseline, and had data available for analysis. | Percentage of participants | NUMBER |
| SECONDARY | Prostate-specific Antigen (PSA) Undetectable Rate | Up to 40 months (through database cut-off date of 12-Dec-2022) | The efficacy analysis population consisted of all randomized participants in the intent to treat population, who had a PSA measurement at baseline, and had data available for analysis. | Percentage of participants | NUMBER |
| SECONDARY | Objective Response (OR) Per Prostate Cancer Working Group (PCWG)-Modified Response Evaluation Criteria in Solid Tumors Version 1.1 (RECIST 1.1) by as Assessed by Blinded Independent Central Review | Up to 40 months (through database cut-off date of 12-Dec-2022) | The efficacy analysis population consisted of all randomized participants. Participants were included in the treatment group to which they were randomized. | Percentage of participants | NUMBER |
| SECONDARY | Duration of Response (DOR) Per Prostate Cancer Working Group (PCWG)-Modified Response Evaluation Criteria in Solid Tumors Version 1.1 (RECIST 1.1) by as Assessed by Blinded Independent Central Review | Up to 40 months (through database cut-off date of 12-Dec-2022) | The efficacy analysis population consisted of all randomized participants. Participants were included in the treatment group to which they were randomized. | Months | MEDIAN |
| SECONDARY | Time to Prostate-specific Antigen (PSA) Progression | Up to 40 months (through database cut-off date of 12-Dec-2022) | The efficacy analysis population consisted of all randomized participants. Participants were included in the treatment group to which they were randomized. | Months | MEDIAN |
| SECONDARY | Time to Radiographic Soft Tissue Progression Per Soft Tissue Rules of Prostate Cancer Working Group (PCWG)-Modified Response Evaluation Criteria in Solid Tumors Version 1.1 (RECIST 1.1) by as Assessed by Blinded Independent Central Review | Up to 40 months (through database cut-off date of 12-Dec-2022) | The efficacy analysis population consisted of all randomized participants. Participants were included in the treatment group to which they were randomized. | Months | MEDIAN |
| SECONDARY | 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) | Up to 40 months (through database cut-off date of 12-Dec-2022) | All participants in the patient-reported outcomes (PRO) full analysis set who received at least 1 dose of study treatment and who had at least 1 PRO assessment available. Participants were included in the treatment group to which they were randomized. | Months | MEDIAN |
1 to 10 of 13Source ClinicalTrials.gov
See all 13 outcomesResults by group26
Each measurement the trial posted, group by group, in the words and numbers it posted.
| Outcome | Group | Category | Value | Spread | Units |
|---|---|---|---|---|---|
| Overall Survival (OS) | Pembrolizumab + Enzalutamide | 24.7 | 95% Confidence Interval 22.0 to 26.8 | Months | |
| Overall Survival (OS) | Placebo + Enzalutamide | 27.3 | 95% Confidence Interval 24.5 to 30.1 | Months | |
Radiographic Progression-free Survival (rPFS) Per Prostate Cancer Working Group (PCWG)-Modified Response Evaluation Criteria in Solid Tumors Version 1.1 (RECIST 1.1) as Assessed by Blinded Independent Central Review | Pembrolizumab + Enzalutamide | 10.4 | 95% Confidence Interval 8.4 to 12.5 | Months | |
Radiographic Progression-free Survival (rPFS) Per Prostate Cancer Working Group (PCWG)-Modified Response Evaluation Criteria in Solid Tumors Version 1.1 (RECIST 1.1) as Assessed by Blinded Independent Central Review | Placebo + Enzalutamide | 9.0 | 95% Confidence Interval 8.3 to 11.5 | Months | |
| Time to Initiation of the First Subsequent Anti-cancer Therapy or Death (TFST) | Pembrolizumab + Enzalutamide | 13.2 | 95% Confidence Interval 11.7 to 15.7 | Months | |
| Time to Initiation of the First Subsequent Anti-cancer Therapy or Death (TFST) | Placebo + Enzalutamide | 12.6 | 95% Confidence Interval 11.3 to 14.2 | Months | |
| Prostate-specific Antigen (PSA) Response Rate | Pembrolizumab + Enzalutamide | 49.0 | 95% Confidence Interval 44.9 to 53.1 | Percentage of participants | |
| Prostate-specific Antigen (PSA) Response Rate | Placebo + Enzalutamide | 45.1 | 95% Confidence Interval 41.1 to 49.2 | Percentage of participants | |
| Prostate-specific Antigen (PSA) Undetectable Rate | Pembrolizumab + Enzalutamide | 13.1 | 95% Confidence Interval 10.5 to 16.1 | Percentage of participants | |
| Prostate-specific Antigen (PSA) Undetectable Rate | Placebo + Enzalutamide | 12.6 | 95% Confidence Interval 10.0 to 15.5 | Percentage of participants |
1 to 10 of 26Source ClinicalTrials.gov
See all 26 results by groupParticipant flow8
How many started, completed or left each group, period by period.
| Period | Milestone | Group | Participants | Units counted |
|---|---|---|---|---|
| Overall Study | STARTED | Pembrolizumab + Enzalutamide | 621 | |
| Overall Study | STARTED | Placebo + Enzalutamide | 623 | |
| Overall Study | Treated | Pembrolizumab + Enzalutamide | 615 | |
| Overall Study | Treated | Placebo + Enzalutamide | 620 | |
| Overall Study | COMPLETED | Pembrolizumab + Enzalutamide | 0 | |
| Overall Study | COMPLETED | Placebo + Enzalutamide | 0 | |
| Overall Study | NOT COMPLETED | Pembrolizumab + Enzalutamide | 621 | |
| Overall Study | NOT COMPLETED | Placebo + Enzalutamide | 623 |
Source ClinicalTrials.gov
Adverse events924
Each adverse event the trial posted, group by group: the participants affected out of those at risk.
| Type | Event | Organ system | Group | Affected | At risk | Events |
|---|---|---|---|---|---|---|
| other | Anaemia | Blood and lymphatic system disorders | Pembrolizumab + Enzalutamide | 141 | 615 | 201 |
| other | Anaemia | Blood and lymphatic system disorders | Placebo + Enzalutamide | 103 | 620 | 119 |
| other | Anaemia | Blood and lymphatic system disorders | Pembrolizumab + Enzalutamide Second Course | 0 | 4 | 0 |
| other | Hypothyroidism | Endocrine disorders | Pembrolizumab + Enzalutamide | 76 | 615 | 81 |
| other | Hypothyroidism | Endocrine disorders | Placebo + Enzalutamide | 27 | 620 | 28 |
| other | Hypothyroidism | Endocrine disorders | Pembrolizumab + Enzalutamide Second Course | 0 | 4 | 0 |
| other | Abdominal pain | Gastrointestinal disorders | Pembrolizumab + Enzalutamide | 25 | 615 | 27 |
| other | Abdominal pain | Gastrointestinal disorders | Placebo + Enzalutamide | 34 | 620 | 41 |
| other | Abdominal pain | Gastrointestinal disorders | Pembrolizumab + Enzalutamide Second Course | 0 | 4 | 0 |
| other | Constipation | Gastrointestinal disorders | Pembrolizumab + Enzalutamide | 113 | 615 | 124 |
1 to 10 of 924Source ClinicalTrials.gov
See all 924 adverse eventsAdverse event totals9
The totals the trial posted for each group.
| Total | Group | Affected | At risk |
|---|---|---|---|
| Total, all-cause mortality | Pembrolizumab + Enzalutamide | 295 | 621 |
| Total, all-cause mortality | Placebo + Enzalutamide | 291 | 623 |
| Total, all-cause mortality | Pembrolizumab + Enzalutamide Second Course | 1 | 4 |
| Total, other adverse events | Pembrolizumab + Enzalutamide | 563 | 615 |
| Total, other adverse events | Placebo + Enzalutamide | 551 | 620 |
| Total, other adverse events | Pembrolizumab + Enzalutamide Second Course | 0 | 4 |
| Total, serious adverse events | Pembrolizumab + Enzalutamide | 238 | 615 |
| Total, serious adverse events | Placebo + Enzalutamide | 165 | 620 |
| Total, serious adverse events | Pembrolizumab + Enzalutamide Second Course | 0 | 4 |
Source ClinicalTrials.gov
Papers2
The papers the trial lists on ClinicalTrials.gov.
Grants0
The grants NIH RePORTER links to the trial, newest funded first: NIH's, and some of AHRQ's, CDC's, FDA's and VA's. Each shows its title, principal investigators, organization and funder in its newest year.
None in this release.
Trial comparisons2
Comparisons of the trial's two groups, calculated by ConductScience from the counts it posted.
| Comparison | Source |
|---|---|
| Pembrolizumab + Enzalutamide vs Placebo + Enzalutamide: Number of Participants Who Discontinue Study Treatment Due to an Adverse Event (AE) | Trial comparisons |
| Pembrolizumab + Enzalutamide vs Placebo + Enzalutamide: Number of Participants Who Experience an Adverse Event (AE) | Trial comparisons |
Tests0
The ConductCognition tests this trial's registered outcomes name, as ScienceGraph matched them in trial-tests-2026-11-12-0.2.1.
None in this release.
Data dates
The day each source was copied for this release.
Sources 3
- ClinicalTrials.gov's posted results, through CTTI's AACTFreely available. Acknowledgement requested
- ClinicalTrials.govNo license stated
- NIH RePORTER's clinical studies and project filesPublic domain
Each source's terms
- ClinicalTrials.gov's posted results, through CTTI's AACTClinicalTrials.gov data via Aggregate Analysis of ClinicalTrials.gov (AACT), CTTI. CTTI makes its materials freely available and requests acknowledgement. https://aact.ctti-clinicaltrials.org/documentation/299
- ClinicalTrials.govnone stated
- NIH RePORTER's clinical studies and project filesPublic domain (NIH RePORTER)
ClinicalTrials.gov's data carry an international copyright outside the United States: https://clinicaltrials.gov/about-site/terms-conditions.
For software
Read this trial from software.
The record and each of its lists are JSON, twenty rows a page. No key.
GET https://conductscience.org/api/trials/v1/NCT03834493
GET https://conductscience.org/api/trials/v1/NCT03834493/results?page=2