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Trial details imported from ClinicalTrials.gov

For full trial details, please see the original record at https://clinicaltrials.gov/show/NCT04191096




Registration number
NCT04191096
Ethics application status
Date submitted
5/12/2019
Date registered
9/12/2019
Date last updated
26/11/2020

Titles & IDs
Public title
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)
Scientific 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)
Secondary ID [1] 0 0
2019-003633-41
Secondary ID [2] 0 0
3475-991
Universal Trial Number (UTN)
Trial acronym
Linked study record

Health condition
Health condition(s) or problem(s) studied:
Metastatic Hormone-Sensitive Prostate Cancer 0 0
Condition category
Condition code
Cancer 0 0 0 0
Prostate
Inflammatory and Immune System 0 0 0 0
Allergies

Intervention/exposure
Study type
Interventional
Description of intervention(s) / exposure
Other interventions - Pembrolizumab
Treatment: Drugs - Enzalutamide
Treatment: Surgery - Androgen Deprivation Therapy (ADT)
Other interventions - Placebo

Experimental: Pembrolizumab + Enzalutamide + ADT - Starting on Day 1 of each 21-day cycle, participants receive 200 mg pembrolizumab IV every 3 weeks (Q3W) for up to 35 cycles (approximately 2 years), plus 160 mg enzalutamide taken orally once daily, while maintaining continuous ADT with a luteinizing-hormone releasing hormone (LHRH) agonist or antagonist during study treatment. Participants will continue to receive enzalutamide and ADT until criteria for discontinuation are met.

Placebo Comparator: Placebo + Enzalutamide + ADT - Starting on Day 1 of each 21-day cycle, participants receive placebo IV Q3W for up to 35 cycles (approximately 2 years), plus 160 mg enzalutamide taken orally once daily, while maintaining continuous ADT with a LHRH agonist or antagonist during study treatment. Participants will continue to receive enzalutamide and ADT until criteria for discontinuation are met.


Other interventions: Pembrolizumab
Pembrolizumab is administered as an IV infusion at 200 mg on Day 1 of each 21-day cycle for up to 35 cycles.

Treatment: Drugs: Enzalutamide
Enzalutamide is administered orally as capsules/tablets at a dosage of 160 mg daily. Enzalutamide is administered continuously until criteria for discontinuation are met.

Treatment: Surgery: Androgen Deprivation Therapy (ADT)
Stable regimen of ADT (LHRH agonist or antagonist) at a dose and frequency of administration that is consistent with the local product label.

Other interventions: Placebo
Placebo infusion solution is administered as an IV infusion on Day 1 of each 21-day cycle for up to 35 cycles.

Intervention code [1] 0 0
Other interventions
Intervention code [2] 0 0
Treatment: Drugs
Intervention code [3] 0 0
Treatment: Surgery
Comparator / control treatment
Control group

Outcomes
Primary outcome [1] 0 0
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 - rPFS is defined as the time from randomization to radiographic progression, or death due to any cause, whichever occurs first. rPFS according to PCWG-modified RECIST 1.1 as assessed by Blinded Independent Central Review will be reported for each study arm.
Timepoint [1] 0 0
Up to approximately 77 months
Primary outcome [2] 0 0
Overall Survival (OS) - OS is defined as the time from randomization to death due to any cause. OS will be reported for each study arm.
Timepoint [2] 0 0
Up to approximately 77 months
Secondary outcome [1] 0 0
Time to Initiation of the First Subsequent Anti-cancer Therapy or Death (TFST) - TFST is defined as the time from randomization to initiation of the first subsequent anti-cancer therapy or death, whichever comes first. TFST will be reported for each study arm.
Timepoint [1] 0 0
Up to approximately 77 months
Secondary outcome [2] 0 0
Time to Symptomatic Skeletal-Related Event (TTSSRE) - TTSSRE is defined as the time from randomization to the first Symptomatic Skeletal-Related Event (SSRE), defined as use of external-beam radiation therapy (EBRT) to prevent or relieve skeletal symptoms, occurrence of new symptomatic pathologic bone fracture (vertebral or nonvertebral), occurrence of spinal cord compression, or tumor-related orthopedic surgical intervention, whichever occurs first. TTSSRE will be reported for each study arm.
Timepoint [2] 0 0
Up to approximately 77 months
Secondary outcome [3] 0 0
Time to Prostate-specific Antigen (PSA) Progression - Time to PSA progression is defined as the time from randomization to PSA progression. The 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. Time to PSA progression will be reported for each study arm.
Timepoint [3] 0 0
Up to approximately 77 months
Secondary outcome [4] 0 0
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) as Assessed by Blinded Independent Central Review - Time to radiographic soft tissue progression is defined as the time from randomization to radiographic soft tissue progression, and will be reported for each study arm.
Timepoint [4] 0 0
Up to approximately 77 months
Secondary outcome [5] 0 0
Time to Pain Progression (TTPP) as Assessed by Brief Pain Inventory-Short Form (BPI-SF) Item 3 ("Worst Pain in 24 Hours") and Opiate Use - TTPP is defined as the time from randomization to pain progression. In this study, pain progression will be assessed by participant responses to Item 3 of the BPI-SF ("worst pain in 24 hours") and by participant opiate use, and will be reported for each study arm.
Timepoint [5] 0 0
Up to approximately 77 months
Secondary outcome [6] 0 0
Time from Randomization to Disease Progression as Determined by Investigator Assessment after Next-line of Therapy or Death from Any Cause, Whichever Occurs First (PFS2) - PFS2 is defined as the time from randomization to disease progression as determined by investigator assessment of radiological or clinical progression after next-line of therapy or death from any cause, whichever occurs first. PFS2 will be reported for each study arm.
Timepoint [6] 0 0
Up to approximately 77 months
Secondary outcome [7] 0 0
Prostate-specific Antigen (PSA) Response Rate - PSA response rate is defined as the percentage of participants in the analysis population with PSA decline of =50% from baseline measured twice at least 3 weeks apart, and will be reported for each study arm.
Timepoint [7] 0 0
Up to approximately 77 months
Secondary outcome [8] 0 0
Prostate-specific antigen (PSA) Undetectable Rate - PSA undetectable rate is defined as the percentage of participants in the analysis population with PSA < 0.2 ng/mL during study intervention, and will be reported for each study arm.
Timepoint [8] 0 0
Up to approximately 77 months
Secondary outcome [9] 0 0
Objective Response Rate (ORR) 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 - ORR is defined as the percentage of participants in the analysis population who have a best overall response of either confirmed CR or PR. ORR per PCWG-modified RECIST 1.1 as assessed by Blinded Independent Central Review will be reported for each study arm.
Timepoint [9] 0 0
Up to approximately 77 months
Secondary outcome [10] 0 0
Duration of Response (DOR) 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 - DOR is defined as the time from the earliest date of first documented evidence of confirmed CR or PR until the earliest date of disease progression or death from any cause, whichever occurs first. DOR per PCWG-modified RECIST 1.1 as assessed by Blinded Independent Central Review will be reported for each study arm.
Timepoint [10] 0 0
Up to approximately 77 months
Secondary outcome [11] 0 0
Number of Participants Who Experience an Adverse Event (AE) - An AE is any untoward medical occurrence in a clinical study participant, temporally associated with the use of study intervention, whether or not considered related to the study intervention. An AE can therefore be any unfavorable and unintended sign (including an abnormal laboratory finding), symptom, or disease (new or exacerbated) temporally associated with the use of a study intervention. The number of participants who experience an AE will be reported for each arm.
Timepoint [11] 0 0
Up to approximately 77 months
Secondary outcome [12] 0 0
Number of Participants Who Discontinue Study Treatment Due to an Adverse Event (AE) - An AE is any untoward medical occurrence in a clinical study participant, temporally associated with the use of study intervention, whether or not considered related to the study intervention. An AE can therefore be any unfavorable and unintended sign (including an abnormal laboratory finding), symptom, or disease (new or exacerbated) temporally associated with the use of a study intervention. The number of participants who discontinue study treatment due to an AE will be reported for each arm.
Timepoint [12] 0 0
Up to approximately 77 months

Eligibility
Key inclusion criteria
- Male participants with histologically- or cytologically-confirmed adenocarcinoma of
the prostate without small cell histology

- Has metastatic disease assessed by investigator and verified by BICR by either =2 bone
lesions on bone scan and/or visceral disease by computed tomography/magnetic resonance
imaging (CT/MRI)

- Willing to maintain continuous ADT with a LHRH agonists or antagonists during study
treatment or have a history of bilateral orchiectomy

- Has an Eastern Cooperative Oncology Group (ECOG) performance status of 0 or 1 assessed
within 10 days of randomization

- Participants receiving bone resorptive therapy (including, but not limited to,
bisphosphonate or denosumab) must have been on stable doses prior to randomization

- Has adequate organ function

- Has provided newly obtained core or excisional biopsy (obtained within 12 months of
screening) from soft tissue not previously irradiated (samples from tumors progressing
in a prior site of radiation are allowed). Participants with bone only or bone
predominant disease may provide a bone biopsy sample

- Male participants must agree to the following during the intervention period and for
at least 120 days after the last dose of study intervention: Refrain from donating
sperm PLUS either be abstinent from heterosexual intercourse and agree to remain
abstinent OR agree to use contraception, unless confirmed to be azoospermic

- Male participants must agree to use male condom when engaging in any activity that
allows for passage of ejaculate to another person of any sex
Minimum age
18 Years
Maximum age
No limit
Gender
Males
Can healthy volunteers participate?
No
Key exclusion criteria
- Has a known additional malignancy that is progressing or has required active treatment
in the last 3 years

- Has an active autoimmune disease that has required systemic treatment in past 2 years

- Has a diagnosis of immunodeficiency or is receiving chronic systemic steroid therapy

- Has undergone major surgery including local prostate intervention (excluding prostate
biopsy) within 28 days prior to randomization and not recovered adequately from the
toxicities and/or complications

- Has a gastrointestinal disorder affecting absorption or is unable to swallow
tablets/capsules

- Has an active infection (including tuberculosis) requiring systemic therapy

- Has a history of (non-infectious) pneumonitis that required steroids or has current
pneumonitis

- Has known active human immunodeficiency virus (HIV), hepatitis B virus (HBV) or
hepatitis C virus (HCV) infection

- Has known or suspected central nervous system (CNS) metastases and/or carcinomatous
meningitis

- Has a history of seizure or any condition that may predispose to seizure

- Has a history of loss of consciousness within 12 months of screening

- Has had myocardial infarction or uncontrolled angina within 6 months prior to
randomization, or has New York Heart Association class III or IV congestive heart
failure or a history of New York Heart Association class III or IV congestive heart
failure

- Has hypotension (systolic blood pressure <86 millimeters of mercury [mmHg]) or
uncontrolled hypertension (systolic blood pressure >170 mmHg or diastolic blood
pressure >105 mmHg) at the screening visit

- Has a history of clinically significant ventricular arrhythmias

- Has hypersensitivity to pembrolizumab and/or enzalutamide and/or any of their
excipients

- Has received prior ADT as neoadjuvant/adjuvant therapy for non-metastatic prostate
cancer for >39 months in duration or within 9 months prior to randomization or with
evidence of disease progression while receiving ADT

- Has had prior treatment with a next generation hormonal agent (eg, abiraterone,
enzalutamide, apalutamide, darolutamide)

- Has received prior therapy with an anti-programmed cell death-1 (anti-PD-1),
anti-programmed cell death-ligand 1 (anti-PD-L1), or anti PD-L2 agent or with an agent
directed to another stimulatory or coinhibitory T-cell receptor

- Has received a live vaccine within 30 days prior to randomization

- Has a "superscan" bone scan

- Has had an allogenic tissue/solid organ transplant

- Is expecting to conceive or father children within the projected duration of the
study, starting with the screening visit through 120 days after the last dose of study
treatment

- Has received any prior pharmacotherapy, radiation therapy or surgery for metastatic
prostate cancer with the following exceptions:

1. Up to 3 months of ADT or orchiectomy with or without concurrent first-generation
antiandrogens, if patient was not treated with docetaxel

2. May have 1 course of palliative radiation or surgical therapy to treat symptoms
resulting from metastatic disease if it was administered at least 4 weeks prior
to randomization

3. For participants with low volume metastatic disease, may have 1 course of
definitive radiotherapy if it was administered at least 4 weeks prior to
randomization

4. Up to 6 cycles of docetaxel therapy with final treatment administration completed
within 2 months of randomization and no evidence of disease progression. In these
participants up to 6 months of ADT permitted

Study design
Purpose of the study
Treatment
Allocation to intervention
Randomised controlled trial
Procedure for enrolling a subject and allocating the treatment (allocation concealment procedures)
Methods used to generate the sequence in which subjects will be randomised (sequence generation)
Masking / blinding
Blinded (masking used)
Who is / are masked / blinded?
The people receiving the treatment/s


The people analysing the results/data
Intervention assignment
Parallel
Other design features
Phase
Phase 3
Type of endpoint(s)
Statistical methods / analysis

Recruitment
Recruitment status
Recruiting
Data analysis
Reason for early stopping/withdrawal
Other reasons
Date of first participant enrolment
Anticipated
Actual
Date of last participant enrolment
Anticipated
Actual
Date of last data collection
Anticipated
Actual
Sample size
Target
Accrual to date
Final
Recruitment in Australia
Recruitment state(s)
NSW,QLD,VIC,WA
Recruitment hospital [1] 0 0
Chris OBrien Lifehouse ( Site 0300) - Camperdown
Recruitment hospital [2] 0 0
Port Macquarie Base Hospital ( Site 0301) - Port Macquarie
Recruitment hospital [3] 0 0
Riverina Cancer Care Center ( Site 0302) - Wagga Wagga
Recruitment hospital [4] 0 0
Gallipoli Medical Research Foundation ( Site 0309) - Greenslopes
Recruitment hospital [5] 0 0
John Flynn Hospital & Medical Centre ( Site 0308) - Tugun
Recruitment hospital [6] 0 0
Monash Health ( Site 0305) - Clayton
Recruitment hospital [7] 0 0
Peter MacCallum Cancer Centre ( Site 0306) - Melbourne
Recruitment hospital [8] 0 0
Fiona Stanley Hospital ( Site 0311) - Murdoch
Recruitment postcode(s) [1] 0 0
2050 - Camperdown
Recruitment postcode(s) [2] 0 0
2444 - Port Macquarie
Recruitment postcode(s) [3] 0 0
2650 - Wagga Wagga
Recruitment postcode(s) [4] 0 0
4120 - Greenslopes
Recruitment postcode(s) [5] 0 0
4224 - Tugun
Recruitment postcode(s) [6] 0 0
3168 - Clayton
Recruitment postcode(s) [7] 0 0
3000 - Melbourne
Recruitment postcode(s) [8] 0 0
6150 - Murdoch
Recruitment outside Australia
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United States of America
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Alaska
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Washington
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Russian Federation
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Moskva
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Taoyuan
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State/province [130] 0 0
Istanbul
Country [131] 0 0
Turkey
State/province [131] 0 0
Izmir
Country [132] 0 0
United Kingdom
State/province [132] 0 0
Aberdeen City
Country [133] 0 0
United Kingdom
State/province [133] 0 0
Cornwall
Country [134] 0 0
United Kingdom
State/province [134] 0 0
England

Funding & Sponsors
Primary sponsor type
Commercial sector/Industry
Name
Merck Sharp & Dohme Corp.
Address
Country

Ethics approval
Ethics application status

Summary
Brief summary
This study will assess the efficacy and safety of pembrolizumab plus enzalutamide plus 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).
Trial website
https://clinicaltrials.gov/show/NCT04191096
Trial related presentations / publications
Public notes

Contacts
Principal investigator
Name 0 0
Medical Director
Address 0 0
Merck Sharp & Dohme Corp.
Country 0 0
Phone 0 0
Fax 0 0
Email 0 0
Contact person for public queries
Name 0 0
Toll Free Number
Address 0 0
Country 0 0
Phone 0 0
1-888-577-8839
Fax 0 0
Email 0 0
Trialsites@merck.com
Contact person for scientific queries

Summary results
For IPD and results data, please see https://clinicaltrials.gov/show/NCT04191096