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Pembrolizumab + Epacadostat vs Pembrolizumab + Placebo in Recurrent or Progressive Metastatic Urothelial Carcinoma

A Phase 3 Randomized, Double-Blind Clinical Study of Pembrolizumab + Epacadostat vs Pembrolizumab + Placebo as a Treatment for Recurrent or Progressive Metastatic Urothelial Carcinoma in Patients Who Have Failed a First-Line Platinum-containing Chemotherapy Regimen for Advanced/Metastatic Disease (KEYNOTE-698/ECHO-303)

Status
Completed
Phases
Phase 3
Study type
Interventional
Source
ClinicalTrials.gov
Registry ID
NCT03374488
Enrollment
84
Registered
2017-12-15
Start date
2017-12-22
Completion date
2020-07-23
Last updated
2025-08-22

For informational purposes only — not medical advice. Sourced from public registries and may not reflect the latest updates. Terms

Conditions

UC (Urothelial Cancer)

Keywords

Urothelial carcinoma, programmed cell death protein 1 (PD-1) inhibitor, indoleamine 2,3-dioxygenase (IDO) inhibitor

Brief summary

The purpose of this study was to evaluate the efficacy and safety of pembrolizumab + epacadostat vs pembrolizumab + placebo as a treatment for recurrent or progressive metastatic urothelial carcinoma in patients who have failed a first-line platinum-containing chemotherapy regimen for advanced/metastatic disease.

Interventions

DRUGPembrolizumab

Pembrolizumab administered intravenously Day 1 of each cycle every 3 weeks.

DRUGEpacadostat

Epacadostat administered orally twice daily.

DRUGPlacebo

Matching placebo administered orally twice daily.

Sponsors

Merck Sharp & Dohme LLC
CollaboratorINDUSTRY
Incyte Corporation
Lead SponsorINDUSTRY

Study design

Allocation
RANDOMIZED
Intervention model
PARALLEL
Primary purpose
TREATMENT
Masking
NONE

Masking description

The study will be unblinded after the last participant completes Week 9 imaging assessment for efficacy analysis and after appropriate EC/IRB approvals have been received.

Eligibility

Sex/Gender
ALL
Age
18 Years to No maximum
Healthy volunteers
No

Inclusion criteria

* Histologically-confirmed diagnosis of urothelial carcinoma of the renal pelvis, ureter, bladder, or urethra, that is transitional cell, or mixed transitional/non-transitional (predominantly transitional) cell type. * Progression or recurrence of urothelial carcinoma following one prior platinum containing chemotherapy regimen for metastatic or unresectable locally advanced disease. A participant who receives a neoadjuvant or adjuvant platinum-containing regimen following cystectomy for localized muscle-invasive urothelial carcinoma is acceptable (without further systemic treatment), if recurrence/progression occurs ≤ 12 months following completion of therapy. * Measurable disease based on RECIST v1.1. * Have provided an archival tumor tissue sample or newly obtained core or excisional biopsy of a tumor lesion not previously irradiated for PD-L1 analysis. * Eastern Cooperative Oncology Group (ECOG) performance status of 0 or 1. * Adequate organ function per protocol-defined criteria.

Exclusion criteria

* Urothelial carcinoma that is suitable for local therapy with curative intent. * History or presence of an abnormal electrocardiogram (ECG) that, in the investigator's opinion, is clinically meaningful. * Known additional malignancy that is progressing or has required active treatment within the past 3 years. * Known active central nervous system (CNS) metastases and/or carcinomatous meningitis. Participants with previously treated brain metastases may participate provided they are radiologically stable, ie, without evidence of progression for at least 4 weeks by repeat imaging. * Active autoimmune disease that has required systemic treatment in past 2 years. * Known history of human immunodeficiency virus (HIV) infection. HIV testing is not required unless mandated by local health authority. * Known history of or is positive for active hepatitis B (HBsAg reactive) or has active hepatitis C (HCV RNA). Note: Testing must be performed to determine eligibility. * Use of protocol-defined prior/concomitant therapy.

Design outcomes

Primary

MeasureTime frameDescription
Objective Response Rate (ORR) With Pembrolizumab + Epacadostat Versus Pembrolizumab + Placeboup to 9 weeks +14 daysORR was defined as the percentage of participants who had a complete response (CR), disappearance of all target lesions or partial response (PR), \>=30% decrease in the sum of the longest diameter of target lesions per RECIST v1.1 by investigator determination.

Secondary

MeasureTime frameDescription
Safety and Tolerability of Pembrolizumab + Epacadostat Versus Pembrolizumab + Placebo as Measured by Number of Participants Experiencing Adverse Events (AEs)Up to 8 monthsAE is defined as any untoward medical occurrence in a patient or clinical study participant, temporally associated with the use of study treatment, whether or not considered related to the study treatment.
Safety and Tolerability of Pembrolizumab + Epacadostat Versus Pembrolizumab + Placebo as Measured by Number of Participants Discontinuing Study Treatment Due to AEUp to 8 monthsAE is defined as any untoward medical occurrence in a patient or clinical study participant, temporally associated with the use of study treatment, whether or not considered related to the study treatment.

Countries

Australia, Canada, Denmark, France, Germany, Hungary, Ireland, Israel, Italy, Japan, Netherlands, Russia, South Korea, Spain, Taiwan, Turkey (Türkiye), United Kingdom, United States

Participant flow

Recruitment details

This study was conducted at 82 centers in 16 countries.

Participants by arm

ArmCount
Pembrolizumab 200 mg + Epacadostat 100 mg BID
Pembrolizumab administered intravenously Day 1 of each cycle every 3 weeks. Epacadostat administered orally twice daily.
42
Pembrolizumab 200 mg + Placebo BID
Pembrolizumab administered intravenously Day 1 of each cycle every 3 weeks. Matching placebo administered orally twice daily.
42
Total84

Withdrawals & dropouts

PeriodReasonFG000FG001
Overall StudyDeath1313
Overall StudyPhysician Decision30
Overall StudyWithdrawal by Subject31

Baseline characteristics

CharacteristicPembrolizumab 200 mg + Epacadostat 100 mg BIDPembrolizumab 200 mg + Placebo BIDTotal
Age, Continuous67.9 years
STANDARD_DEVIATION 8.7
65.2 years
STANDARD_DEVIATION 10
66.5 years
STANDARD_DEVIATION 9.4
Ethnicity (NIH/OMB)
Hispanic or Latino
0 Participants0 Participants0 Participants
Ethnicity (NIH/OMB)
Not Hispanic or Latino
38 Participants37 Participants75 Participants
Ethnicity (NIH/OMB)
Unknown or Not Reported
4 Participants5 Participants9 Participants
Metastasis Status at Screening
Advanced/Unresectable
7 Participants2 Participants9 Participants
Metastasis Status at Screening
Metastatic
35 Participants40 Participants75 Participants
Race/Ethnicity, Customized
Asian
5 Participants6 Participants11 Participants
Race/Ethnicity, Customized
Missing
2 Participants4 Participants6 Participants
Race/Ethnicity, Customized
White
35 Participants32 Participants67 Participants
Sex: Female, Male
Female
7 Participants5 Participants12 Participants
Sex: Female, Male
Male
35 Participants37 Participants72 Participants

Adverse events

Event typeEG000
affected / at risk
EG001
affected / at risk
EG002
affected / at risk
deaths
Total, all-cause mortality
14 / 4218 / 4132 / 83
other
Total, other adverse events
39 / 4235 / 4174 / 83
serious
Total, serious adverse events
22 / 4216 / 4138 / 83

Outcome results

Primary

Objective Response Rate (ORR) With Pembrolizumab + Epacadostat Versus Pembrolizumab + Placebo

ORR was defined as the percentage of participants who had a complete response (CR), disappearance of all target lesions or partial response (PR), \>=30% decrease in the sum of the longest diameter of target lesions per RECIST v1.1 by investigator determination.

Time frame: up to 9 weeks +14 days

Population: The Intention-to-Treat (ITT) population consisted of all randomized participants. Responses are based on Investigator assessments per RECIST 1.1 without confirmation using all scans up to week 9 (day 63) + 14 days.

ArmMeasureValue (NUMBER)
Pembrolizumab 200 mg + Epacadostat 100 mg BIDObjective Response Rate (ORR) With Pembrolizumab + Epacadostat Versus Pembrolizumab + Placebo21.4 percentage of participants
Pembrolizumab 200 mg + Placebo BIDObjective Response Rate (ORR) With Pembrolizumab + Epacadostat Versus Pembrolizumab + Placebo9.5 percentage of participants
Secondary

Safety and Tolerability of Pembrolizumab + Epacadostat Versus Pembrolizumab + Placebo as Measured by Number of Participants Discontinuing Study Treatment Due to AE

AE is defined as any untoward medical occurrence in a patient or clinical study participant, temporally associated with the use of study treatment, whether or not considered related to the study treatment.

Time frame: Up to 8 months

Population: All Participants as Treated (APaT) population consisted of all randomized participants who received at least 1 dose of study treatment.

ArmMeasureValue (COUNT_OF_PARTICIPANTS)
Pembrolizumab 200 mg + Epacadostat 100 mg BIDSafety and Tolerability of Pembrolizumab + Epacadostat Versus Pembrolizumab + Placebo as Measured by Number of Participants Discontinuing Study Treatment Due to AE4 Participants
Pembrolizumab 200 mg + Placebo BIDSafety and Tolerability of Pembrolizumab + Epacadostat Versus Pembrolizumab + Placebo as Measured by Number of Participants Discontinuing Study Treatment Due to AE6 Participants
Secondary

Safety and Tolerability of Pembrolizumab + Epacadostat Versus Pembrolizumab + Placebo as Measured by Number of Participants Experiencing Adverse Events (AEs)

AE is defined as any untoward medical occurrence in a patient or clinical study participant, temporally associated with the use of study treatment, whether or not considered related to the study treatment.

Time frame: Up to 8 months

Population: All Participants as Treated (APaT) population consisted of all randomized participants who received at least 1 dose of study treatment.

ArmMeasureValue (COUNT_OF_PARTICIPANTS)
Pembrolizumab 200 mg + Epacadostat 100 mg BIDSafety and Tolerability of Pembrolizumab + Epacadostat Versus Pembrolizumab + Placebo as Measured by Number of Participants Experiencing Adverse Events (AEs)42 Participants
Pembrolizumab 200 mg + Placebo BIDSafety and Tolerability of Pembrolizumab + Epacadostat Versus Pembrolizumab + Placebo as Measured by Number of Participants Experiencing Adverse Events (AEs)39 Participants

Source: ClinicalTrials.gov · Data processed: Feb 24, 2026