A Study of Pembrolizumab (MK-3475) Versus Paclitaxel for Participants With Advanced Gastric/Gastroesophageal Junction Adenocarcinoma That Progressed After Therapy With Platinum and Fluoropyrimidine (MK-3475-061/KEYNOTE-061)

Phase 3

Completed

Conditions: Gastric Adenocarcinoma
Gastroesophageal Junction Adenocarcinoma

Interventions: Biological: pembrolizumab
Drug: paclitaxel

Registration Number: NCT02370498

Lead Sponsor: Merck Sharp & Dohme LLC

Brief Summary: This is a study for participants with advanced gastric or gastroesophageal junction adenocarcinoma who have had tumor progression after first-line treatment with platinum and fluoropyrimidine doublet therapy. The primary study hypotheses are that pembrolizumab (MK-3475) prolongs progression free survival (PFS) and overall survival (OS) for participants with tumors that show positive programmed cell death ligand 1 (PD-L1) expression.

As of 20-March-2016, enrollment will be limited to PD-L1 positive participants.

Detailed Description: Not available

Recruitment & Eligibility

Status: COMPLETED

Sex: All

Target Recruitment: 592

Inclusion Criteria

Histologically- or cytologically-confirmed diagnosis of gastric or gastroesophageal junction adenocarcinoma
Confirmed metastatic or locally advanced, unresectable disease (by computed tomography [CT] scan or clinical evidence)
Eastern Cooperative Oncology Group (ECOG) performance status of 0 or 1
Progression on or after prior first-line therapy containing any platinum/fluoropyrimidine doublet
Willing to provide tumor tissue for PD-L1 biomarker analysis (new or archived specimens with agreement of Sponsor). As of 20 March 2016, participants must be PD-L1 positive to be enrolled.
Human epidermal growth factor receptor 2 (HER-2/neu) status known and participants with HER2/neu positive tumors show documentation of disease progression on treatment containing trastuzumab
Female participants of childbearing potential should be willing to use 2 methods of birth control or be surgically sterile, or abstain from heterosexual activity for the course of the study through 120 days after the last dose of pembrolizumab or through 180 days after the last dose of paclitaxel.
Male participants should agree to use an adequate method of contraception starting with the first dose of study therapy through 120 days after the last dose of pembrolizumab or through 180 days after the last dose of paclitaxel.
Adequate organ function

Exclusion Criteria

Currently participating and receiving study therapy, or participated in a study of an investigational agent and received study therapy or used an investigation device within 4 weeks of the first dose of medication
Squamous cell or undifferentiated gastric cancer
Active autoimmune disease that has required systemic treatment in past 2 years (replacement therapy is not considered a form of systemic treatment
Diagnosis of immunodeficiency or receiving systemic steroid therapy or any other form of immunosuppressive therapy within 7 days prior to the first dose of study medication
Prior anti-cancer monoclonal antibody (mAb) within 4 weeks prior to study Day 1 or not recovered from AEs due to agents administered more than 4 weeks earlier
Prior chemotherapy, targeted small molecule therapy, or radiation therapy within 2 weeks prior to study Day 1 or not recovered from adverse events due to a previously administered agent or surgery
Known additional malignancy that is progressing or requires active treatment (with the exception of basal cell carcinoma of the skin, squamous cell carcinoma of the skin, or in situ cervical cancer that has undergone potentially curative therapy)
Known active central nervous system (CNS) metastases and/or carcinomatous meningitis
History of (noninfectious) pneumonitis that required steroids or current pneumonitis
Active infection requiring systemic therapy
Known psychiatric or substance abuse disorders that would interfere with cooperation with the requirements of the trial
Pregnant or breastfeeding, or expecting to conceive or father children within the projected duration of the trial, starting with the screening visit through 120 days after the last dose of pembrolizumab or through 180 days after the last dose of paclitaxel.
Prior immunotherapy including anti-PD-1, anti-PD-L1, or anti-PD-L2 agent, or previously participated in Merck pembrolizumab (MK-3475) clinical trial
Known history of human immunodeficiency virus (HIV)
Known active Hepatitis B or Hepatitis C
Live vaccine within 30 days of planned start of study therapy
Known allergy or hypersensitivity to paclitaxel or any components used in the paclitaxel preparation or other contraindication for taxane therapy

Study & Design

Study Type: INTERVENTIONAL

Study Design: PARALLEL

Arm && Interventions

Group	Intervention	Description
Pembrolizumab	pembrolizumab	Participants receive 200 mg intravenous (IV) pembrolizumab on Day 1 of each 21-day cycle, for up to 35 administrations (approximately 2 years).
Paclitaxel	paclitaxel	Participants receive 80 mg/m\^2 IV paclitaxel on Days 1, 8, and 15 of each 28-day cycle, until disease progression or unacceptable toxicity.

Primary Outcome Measures

Name	Time	Method
Progression-free Survival (PFS) According to Response Criteria in Solid Tumors Version 1.1 (RECIST 1.1) Based on Blinded Independent Central Review (BICR) in Programmed Death-Ligand 1 (PD-L1) Positive Participants	Up to 30 months (through database cut-off date of 26 Oct 2017)	PFS was defined as the time from randomization to the first documented disease progression per RECIST 1.1 based on BICR, or death due to any cause, whichever occurs first. According to RECIST 1.1, progressive disease (PD) was defined as a 20% relative increase in the sum of diameters (SOD) of target lesions, taking as reference the nadir SOD and an absolute increase of \>5 mm in the SOD, or the appearance of new lesions. PFS was analyzed using the Kaplan-Meier method and median PFS (95% confidence interval \[CI\]) in months was reported for PD-L1 positive participants by treatment group.
Overall Survival (OS) in PD-L1 Positive Participants	Up to 30 months (through database cut-off date of 26 Oct 2017)	OS was defined as the time from randomization to death due to any cause. Participants without documented death at the time of the final analysis were censored at the date of the last follow-up. OS was analyzed using the Kaplan-Meier method and median OS (95% CI) in months was reported for PD-L1 positive participants by treatment group.

Secondary Outcome Measures

Name	Time	Method
PFS According to RECIST 1.1 Based on BICR in All Participants	Up to 30 months (through database cut-off date of 26 Oct 2017)	PFS was defined as the time from randomization to the first documented disease progression per RECIST 1.1 based on BICR, or death due to any cause, whichever occurs first. According to RECIST 1.1, PD was defined as a 20% relative increase in the SOD of target lesions, taking as reference the nadir SOD and an absolute increase of \>5 mm in the SOD, or the appearance of new lesions. PFS was analyzed using the Kaplan-Meier method and median PFS (95% CI) in months was reported for all participants by treatment group.
OS in All Participants	Up to 30 months (through database cut-off date of 26 Oct 2017)	OS was defined as the time from randomization to death due to any cause. Participants without documented death at the time of the final analysis were censored at the date of the last follow-up. OS was analyzed using the Kaplan-Meier method and median OS (95% CI) in months was reported for all participants by treatment group.
PFS According to RECIST 1.1 Based on Investigator Assessment in PD-L1 Positive Participants	Up to 30 months (through database cut-off date of 26 Oct 2017)	PFS was defined as the time from randomization to the first documented disease progression per RECIST 1.1 based on investigator assessment, or death due to any cause, whichever occurs first. According to RECIST 1.1, PD was defined as a 20% relative increase in the SOD of target lesions, taking as reference the nadir SOD and an absolute increase of \>5 mm in the SOD, or the appearance of new lesions. PFS was analyzed using the Kaplan-Meier method and median PFS (95% CI) in months was reported for PD-L1 positive participants by treatment group.
ORR According to RECIST 1.1 Based on Investigator Assessment in All Participants	Up to 30 months (through database cut-off date of 26 Oct 2017)	ORR was defined as the percentage of the participants in the analysis population who had a confirmed CR (disappearance of all non-nodal target lesions and any pathological lymph nodes must have become normal) or PR (at least a 30% decrease in the SOD of target lesions, taking as reference the baseline SOD) according to RECIST 1.1 and based on investigator assessment. ORR was analyzed using the stratified Miettinen and Nurminen method, and reported with 95% CI for all participants by treatment group.
Duration of Response (DOR) According to RECIST 1.1 Based on BICR in PD-L1 Positive Participants	Up to 30 months (through database cut-off date of 26 Oct 2017)	For PD-L1 positive participants who demonstrated CR (disappearance of all non-nodal target lesions and any pathological lymph nodes must have become normal) or PR (at least a 30% decrease in the SOD of target lesions, taking as reference the baseline SOD) according to RECIST 1.1 and based on BICR, DOR was defined as the time from first documented evidence of CR or PR until disease progression or death due to any cause, whichever occurs first. DOR for participants who had not progressed or died at the time of analysis was censored at the date of their last tumor assessment. DOR was analyzed using the Kaplan-Meier method and median DOR (range) in months was reported for PD-L1 positive participants with response by treatment group.
DOR According to RECIST 1.1 Based on BICR in All Participants	Up to 30 months (through database cut-off date of 26 Oct 2017)	For participants who demonstrated CR (disappearance of all non-nodal target lesions and any pathological lymph nodes must have become normal) or PR (at least a 30% decrease in the SOD of target lesions, taking as reference the baseline SOD) according to RECIST 1.1 and based on BICR, DOR was defined as the time from first documented evidence of CR or PR until disease progression or death due to any cause, whichever occurs first. DOR for participants who had not progressed or died at the time of analysis was censored at the date of their last tumor assessment. DOR was analyzed using the Kaplan-Meier method and median DOR (range) in months was reported for all participants with response by treatment group.
DOR According to RECIST 1.1 Based on Investigator Assessment in PD-L1 Positive Participants	Up to 30 months (through database cut-off date of 26 Oct 2017)	For PD-L1 positive participants who demonstrated CR (disappearance of all non-nodal target lesions and any pathological lymph nodes must have become normal) or PR (at least a 30% decrease in the SOD of target lesions, taking as reference the baseline SOD) according to RECIST 1.1 and based on investigator assessment, DOR was defined as the time from first documented evidence of CR or PR until disease progression or death due to any cause, whichever occurs first. DOR for participants who had not progressed or died at the time of analysis was censored at the date of their last tumor assessment. DOR was analyzed using the Kaplan-Meier method and median DOR (range) in months was reported for PD-L1 positive participants with response by treatment group.
DOR According to RECIST 1.1 Based on Investigator Assessment in All Participants	Up to 30 months (through database cut-off date of 26 Oct 2017)	For participants who demonstrated CR (disappearance of all non-nodal target lesions and any pathological lymph nodes must have become normal) or PR (at least a 30% decrease in the SOD of target lesions, taking as reference the baseline SOD) according to RECIST 1.1 and based on investigator assessment, DOR was defined as the time from first documented evidence of CR or PR until disease progression or death due to any cause, whichever occurs first. DOR for participants who had not progressed or died at the time of analysis was censored at the date of their last tumor assessment. DOR was analyzed using the Kaplan-Meier method and median DOR (range) in months was reported for all participants with response by treatment group.
PFS According to RECIST 1.1 Based on Investigator Assessment in All Participants	Up to 30 months (through database cut-off date of 26 Oct 2017)	PFS was defined as the time from randomization to the first documented disease progression per RECIST 1.1 based on investigator assessment, or death due to any cause, whichever occurs first. According to RECIST 1.1, PD was defined as a 20% relative increase in the SOD of target lesions, taking as reference the nadir SOD and an absolute increase of \>5 mm in the SOD, or the appearance of new lesions. PFS was analyzed using the Kaplan-Meier method and median PFS (95% CI) in months was reported for all participants by treatment group.
PFS According to Immune-Related Response Evaluation Criteria in Solid Tumors (irRECIST) Based on BICR in PD-L1 Positive Participants	Up to 30 months (through database cut-off date of 26 Oct 2017)	PFS defined as time from randomization to first documented PD per irRECIST based on BICR, or death due to any cause, whichever occurs first. Following initial PD by RECIST 1.1 (20% relative increase in SOD of target lesions), participants were assessed according to irRECIST: tumor assessment was repeated ≥4 weeks later to confirm PD with the option of continuing treatment until this scan was obtained for clinically stable participants. If PD confirmed, participant was discontinued from treatment unless investigator determined benefit. If repeat scan indicated stable disease (SD; neither sufficient shrinkage or increase of target lesion), partial response (PR; ≥30% decrease in the SOD of target lesions), or complete response (CR; disappearance of all non-nodal target lesions), participant could continue treatment at investigator's discretion. PFS analyzed using Kaplan-Meier method and median PFS (95% CI) in months was reported for PD-L1 positive participants by treatment group.
PFS According to irRECIST Based on BICR in All Participants	Up to 30 months (through database cut-off date of 26 Oct 2017)	PFS defined as time from randomization to first documented PD per irRECIST based on BICR, or death due to any cause, whichever occurs first. Following initial PD by RECIST 1.1 (20% relative increase in SOD of target lesions), participants were assessed according to irRECIST: tumor assessment was repeated ≥4 weeks later to confirm PD with the option of continuing treatment until this scan was obtained for clinically stable participants. If PD confirmed, participant was discontinued from treatment unless investigator determined benefit. If repeat scan indicated SD (neither sufficient shrinkage or increase of target lesion), PR (≥30% decrease in the SOD of target lesions), or CR (disappearance of all non-nodal target lesions), participant could continue treatment at investigator's discretion. PFS analyzed using Kaplan-Meier method and median PFS (95% CI) in months was reported for all participants by treatment group.
Time to Tumor Progression (TTP) According to RECIST 1.1 Based on BICR in PD-L1 Positive Participants	Up to 30 months (through database cut-off date of 26 Oct 2017)	TTP was defined as the time from randomization to the first documented disease progression per RECIST 1.1 based on BICR. Using RECIST 1.1, progressive disease was defined as a 20% relative increase in the SOD of target lesions, taking as reference the nadir SOD and an absolute increase of \>5 mm in the SOD, or the appearance of new lesions. If there was no documented disease progression, TTP was censored at last tumor assessment date. TTP was analyzed using the Kaplan-Meier method and median TTP (95% CI) in months was reported for PD-L1 positive participants by treatment group.
TTP According to RECIST 1.1 Based on BICR in All Participants	Up to 30 months (through database cut-off date of 26 Oct 2017)	TTP was defined as the time from randomization to the first documented disease progression per RECIST 1.1 based on BICR. Using RECIST 1.1, progressive disease was defined as a 20% relative increase in the SOD of target lesions, taking as reference the nadir SOD and an absolute increase of \>5 mm in the SOD, or the appearance of new lesions. If there was no documented disease progression, TTP was censored at last tumor assessment date. TTP was analyzed using the Kaplan-Meier method and median TTP (95% CI) in months was reported for all participants by treatment group.
Objective Response Rate (ORR) According to RECIST 1.1 Based on BICR in PD-L1 Positive Participants	Up to 30 months (through database cut-off date of 26 Oct 2017)	ORR was defined as the percentage of the participants in the analysis population who had a confirmed CR (disappearance of all non-nodal target lesions and any pathological lymph nodes must have become normal) or PR (at least a 30% decrease in the SOD of target lesions, taking as reference the baseline SOD) according to RECIST 1.1 and based on BICR. ORR was analyzed using the stratified Miettinen and Nurminen method, and reported with 95% CI for PD-L1 positive participants by treatment group.
ORR According to RECIST 1.1 Based on BICR in All Participants	Up to 30 months (through database cut-off date of 26 Oct 2017)	ORR was defined as the percentage of the participants in the analysis population who had a confirmed CR (disappearance of all non-nodal target lesions and any pathological lymph nodes must have become normal) or PR (at least a 30% decrease in the SOD of target lesions, taking as reference the baseline SOD) according to RECIST 1.1 and based on BICR. ORR was analyzed using the stratified Miettinen and Nurminen method, and reported with 95% CI for all participants by treatment group.
ORR According to RECIST 1.1 Based on Investigator Assessment in PD-L1 Positive Participants	Up to 30 months (through database cut-off date of 26 Oct 2017)	ORR was defined as the percentage of the participants in the analysis population who had a confirmed CR (disappearance of all non-nodal target lesions and any pathological lymph nodes must have become normal) or PR (at least a 30% decrease in the SOD of target lesions, taking as reference the baseline SOD) according to RECIST 1.1 and based on investigator assessment. ORR was analyzed using the stratified Miettinen and Nurminen method, and reported with 95% CI for PD-L1 positive participants by treatment group.
TTP According to RECIST 1.1 Based on Investigator Assessment in PD-L1 Positive Participants	Up to 30 months (through database cut-off date of 26 Oct 2017)	TTP was defined as the time from randomization to the first documented disease progression per RECIST 1.1 based on investigator assessment. Using RECIST 1.1, progressive disease was defined as a 20% relative increase in the SOD of target lesions, taking as reference the nadir SOD and an absolute increase of \>5 mm in the SOD, or the appearance of new lesions. If there was no documented disease progression, TTP was censored at last tumor assessment date. TTP was analyzed using the Kaplan-Meier method and median TTP (95% CI) in months was reported for PD-L1 positive participants by treatment group.
TTP According to RECIST 1.1 Based on Investigator Assessment in All Participants	Up to 30 months (through database cut-off date of 26 Oct 2017)	TTP was defined as the time from randomization to the first documented disease progression per RECIST 1.1 based on investigator assessment. Using RECIST 1.1, progressive disease was defined as a 20% relative increase in the SOD of target lesions, taking as reference the nadir SOD and an absolute increase of \>5 mm in the SOD, or the appearance of new lesions. If there was no documented disease progression, TTP was censored at last tumor assessment date. TTP was analyzed using the Kaplan-Meier method and median TTP (95% CI) in months was reported for all participants by treatment group.
Percentage of PD-L1 Positive Participants Who Experienced an Adverse Event (AE)	Up to 71 months (through database cut-off date of 10 Jun 2021)	An AE was defined as any untoward medical occurrence in a participant administered a pharmaceutical product and which does not necessarily have to have a causal relationship with this treatment. An AE could therefore be any unfavourable and unintended sign, symptom, or disease temporally associated with the use of a medicinal product or protocol-specified procedure, whether or not considered related to the medicinal product or protocol-specified procedure. Any worsening of a pre-existing condition that was temporally associated with the use of the Sponsor's product was also an AE. The percentage of participants with at least one AE was reported for PD-L1 positive participants by treatment group.
Percentage of All Participants Who Experienced an AE	Up to 71 months (through database cut-off date of 10 Jun 2021)	An AE was defined as any untoward medical occurrence in a participant administered a pharmaceutical product and which does not necessarily have to have a causal relationship with this treatment. An AE could therefore be any unfavourable and unintended sign, symptom, or disease temporally associated with the use of a medicinal product or protocol-specified procedure, whether or not considered related to the medicinal product or protocol-specified procedure. Any worsening of a pre-existing condition that was temporally associated with the use of the Sponsor's product was also an AE. The percentage of participants with at least one AE was reported for all participants by treatment group.
Percentage of PD-L1 Positive Participants That Discontinued Study Treatment Due to AE	Up to approximately 26.4 months	An AE was defined as any untoward medical occurrence in a participant administered a pharmaceutical product and which does not necessarily have to have a causal relationship with this treatment. An AE could therefore be any unfavourable and unintended sign, symptom, or disease temporally associated with the use of a medicinal product or protocol-specified procedure, whether or not considered related to the medicinal product or protocol-specified procedure. Any worsening of a pre-existing condition that was temporally associated with the use of the Sponsor's product was also an AE. The percentage of participants that discontinued study treatment due to an AE was reported for PD-L1 positive participants by treatment group.
Percentage of All Participants That Discontinued Study Treatment Due to AE	Up to approximately 26.4 months	An AE was defined as any untoward medical occurrence in a participant administered a pharmaceutical product and which does not necessarily have to have a causal relationship with this treatment. An AE could therefore be any unfavourable and unintended sign, symptom, or disease temporally associated with the use of a medicinal product or protocol-specified procedure, whether or not considered related to the medicinal product or protocol-specified procedure. Any worsening of a pre-existing condition that was temporally associated with the use of the Sponsor's product was also an AE. The percentage of participants that discontinued study treatment due to an AE was reported for all participants by treatment group.