Pembrolizumab (MK-3475) Plus Chemotherapy Versus Placebo Plus Chemotherapy in Participants Gastric or Gastroesophageal Junction (GEJ) Adenocarcinoma (MK-3475-859/KEYNOTE-859)-China Extension

Phase 3

Withdrawn

• Conditions: Stomach Neoplasms
• Interventions: Biological: Pembrolizumab; Drug: Cisplatin; Drug: 5-fluorouracil; Drug: Oxaliplatin; Drug: Placebo for Pembrolizumab; Drug: Capecitabine

• Registration Number: NCT04859582
• Lead Sponsor: Merck Sharp & Dohme LLC

Brief Summary

The purpose of this study is to evaluate the efficacy of pembrolizumab (MK-3745) in combination with chemotherapy (Cisplatin combined with 5-Fluorouracil \[FP regimen\] or oxaliplatin combined with capecitabine \[CAPOX regimen\]) versus placebo in combination with chemotherapy (FP or CAPOX regimens) in the treatment of human epidermal growth factor receptor 2 (HER2) negative advanced gastric or GEJ adenocarcinoma in adult Chinese participants.

The primary hypotheses of this study are that pembrolizumab plus chemotherapy is superior to placebo plus chemotherapy in terms of overall survival (OS).

Detailed Description

The China extension study will include participants previously enrolled in China in the global study for MK-3475-859 (NCT03675737) plus those enrolled during the China extension enrollment period. A total of approximately 231 Chinese participants will be enrolled.

Study Timeline

• Study Start: 2018-11-08
• Study First Submitted: 2021-04-23
• Study First Submitted QC: 2021-04-23
• Study First Posted: 2021-04-26
• Status Verified: 2021-12
• Last Update Submitted: 2021-12-15
• Last Update Posted: 2021-12-16
• Primary Completion: 2024-11-29
• Study Completion: 2024-11-29

Recruitment & Eligibility

• Status: WITHDRAWN
• Sex: All
• Target Recruitment: Not specified

Inclusion Criteria

Not provided

Exclusion Criteria

Not provided

Study & Design

• Study Type: INTERVENTIONAL
• Study Design: PARALLEL

Arm && Interventions

Group	Intervention	Description
Placebo + FP or CAPOX	Placebo for Pembrolizumab	Participants receive placebo for pembrolizumab IV on Day 1 Q3W for up to 35 cycles (approximately 2 years) + physicians' choice of either cisplatin 80 mg/m\^2 IV on Day 1 Q3W and 5FU 800 mg/m\^2/day via continuous IV infusion on Days 1 to 5 Q3W OR oxaliplatin 130 mg/m\^2 IV on Day 1 Q3W + capecitabine 1000 mg/m\^2 orally BID on Days 1 to 14 Q3W.
Pembrolizumab + FP or CAPOX	Pembrolizumab	Participants receive pembrolizumab 200 mg intravenously (IV) on Day 1 of each 21-day cycle (Q3W) for up to 35 cycles (approximately 2 years) + physicians' choice of either cisplatin 80 mg/m\^2 IV on Day 1 Q3W and 5-fluorouracil (5FU) 800 mg/m\^2/day via continuous IV infusion on Days 1 to 5 Q3W OR oxaliplatin 130 mg/m\^2 IV on Day 1 Q3W + capecitabine 1000 mg/m\^2 orally twice a day (BID) on Days 1 to 14 Q3W. Participants who complete 35 administrations or achieve a complete response (CR) but progress after discontinuation can initiate a second course of pembrolizumab for up to 17 cycles (approximately 1 additional year).
Pembrolizumab + FP or CAPOX	Cisplatin	Participants receive pembrolizumab 200 mg intravenously (IV) on Day 1 of each 21-day cycle (Q3W) for up to 35 cycles (approximately 2 years) + physicians' choice of either cisplatin 80 mg/m\^2 IV on Day 1 Q3W and 5-fluorouracil (5FU) 800 mg/m\^2/day via continuous IV infusion on Days 1 to 5 Q3W OR oxaliplatin 130 mg/m\^2 IV on Day 1 Q3W + capecitabine 1000 mg/m\^2 orally twice a day (BID) on Days 1 to 14 Q3W. Participants who complete 35 administrations or achieve a complete response (CR) but progress after discontinuation can initiate a second course of pembrolizumab for up to 17 cycles (approximately 1 additional year).
Pembrolizumab + FP or CAPOX	Oxaliplatin	Participants receive pembrolizumab 200 mg intravenously (IV) on Day 1 of each 21-day cycle (Q3W) for up to 35 cycles (approximately 2 years) + physicians' choice of either cisplatin 80 mg/m\^2 IV on Day 1 Q3W and 5-fluorouracil (5FU) 800 mg/m\^2/day via continuous IV infusion on Days 1 to 5 Q3W OR oxaliplatin 130 mg/m\^2 IV on Day 1 Q3W + capecitabine 1000 mg/m\^2 orally twice a day (BID) on Days 1 to 14 Q3W. Participants who complete 35 administrations or achieve a complete response (CR) but progress after discontinuation can initiate a second course of pembrolizumab for up to 17 cycles (approximately 1 additional year).
Pembrolizumab + FP or CAPOX	5-fluorouracil	Participants receive pembrolizumab 200 mg intravenously (IV) on Day 1 of each 21-day cycle (Q3W) for up to 35 cycles (approximately 2 years) + physicians' choice of either cisplatin 80 mg/m\^2 IV on Day 1 Q3W and 5-fluorouracil (5FU) 800 mg/m\^2/day via continuous IV infusion on Days 1 to 5 Q3W OR oxaliplatin 130 mg/m\^2 IV on Day 1 Q3W + capecitabine 1000 mg/m\^2 orally twice a day (BID) on Days 1 to 14 Q3W. Participants who complete 35 administrations or achieve a complete response (CR) but progress after discontinuation can initiate a second course of pembrolizumab for up to 17 cycles (approximately 1 additional year).
Pembrolizumab + FP or CAPOX	Capecitabine	Participants receive pembrolizumab 200 mg intravenously (IV) on Day 1 of each 21-day cycle (Q3W) for up to 35 cycles (approximately 2 years) + physicians' choice of either cisplatin 80 mg/m\^2 IV on Day 1 Q3W and 5-fluorouracil (5FU) 800 mg/m\^2/day via continuous IV infusion on Days 1 to 5 Q3W OR oxaliplatin 130 mg/m\^2 IV on Day 1 Q3W + capecitabine 1000 mg/m\^2 orally twice a day (BID) on Days 1 to 14 Q3W. Participants who complete 35 administrations or achieve a complete response (CR) but progress after discontinuation can initiate a second course of pembrolizumab for up to 17 cycles (approximately 1 additional year).
Placebo + FP or CAPOX	Cisplatin	Participants receive placebo for pembrolizumab IV on Day 1 Q3W for up to 35 cycles (approximately 2 years) + physicians' choice of either cisplatin 80 mg/m\^2 IV on Day 1 Q3W and 5FU 800 mg/m\^2/day via continuous IV infusion on Days 1 to 5 Q3W OR oxaliplatin 130 mg/m\^2 IV on Day 1 Q3W + capecitabine 1000 mg/m\^2 orally BID on Days 1 to 14 Q3W.
Placebo + FP or CAPOX	5-fluorouracil	Participants receive placebo for pembrolizumab IV on Day 1 Q3W for up to 35 cycles (approximately 2 years) + physicians' choice of either cisplatin 80 mg/m\^2 IV on Day 1 Q3W and 5FU 800 mg/m\^2/day via continuous IV infusion on Days 1 to 5 Q3W OR oxaliplatin 130 mg/m\^2 IV on Day 1 Q3W + capecitabine 1000 mg/m\^2 orally BID on Days 1 to 14 Q3W.
Placebo + FP or CAPOX	Oxaliplatin	Participants receive placebo for pembrolizumab IV on Day 1 Q3W for up to 35 cycles (approximately 2 years) + physicians' choice of either cisplatin 80 mg/m\^2 IV on Day 1 Q3W and 5FU 800 mg/m\^2/day via continuous IV infusion on Days 1 to 5 Q3W OR oxaliplatin 130 mg/m\^2 IV on Day 1 Q3W + capecitabine 1000 mg/m\^2 orally BID on Days 1 to 14 Q3W.
Placebo + FP or CAPOX	Capecitabine	Participants receive placebo for pembrolizumab IV on Day 1 Q3W for up to 35 cycles (approximately 2 years) + physicians' choice of either cisplatin 80 mg/m\^2 IV on Day 1 Q3W and 5FU 800 mg/m\^2/day via continuous IV infusion on Days 1 to 5 Q3W OR oxaliplatin 130 mg/m\^2 IV on Day 1 Q3W + capecitabine 1000 mg/m\^2 orally BID on Days 1 to 14 Q3W.

Primary Outcome Measures

Name	Time	Method
Overall Survival (OS)	Up to approximately 65 months	OS is the time from randomization to death due to any cause.

Secondary Outcome Measures

Name	Time	Method
Progression-free Survival (PFS)	Up to approximately 65 months	PFS is defined as the time from randomization to the first documented disease progression or death due to any cause, whichever occurs first. Responses are according to the Response Evaluation Criteria in Solid Tumors version 1.1 (RECIST 1.1) as assessed by blinded independent central review (BICR).
Objective Response Rate (ORR)	Up to approximately 65 months	ORR was defined as the percentage of participants who have a confirmed complete response (CR: disappearance of all target lesions) or partial response (PR: At least a 30% decrease in the sum of diameters of target lesions, taking as reference the baseline sum diameters) per RECIST 1.1 as assessed by BICR.
Percentage of Participants Discontinuing Study Drug Due to AEs	Up to approximately 36 months	Percentage of participants discontinuing study treatment due to an AE.
Percentage of Participants Experiencing Adverse Events (AEs)	Up to approximately 65 months	Percentage of participants experiencing an AE defined as any unfavorable and unintended sign, symptom, disease, or worsening of preexisting condition temporally associated with study therapy and irrespective of causality to study treatment.
Duration of Response (DOR)	Up to approximately 65 months	DOR is determined by disease assessment and is defined as the time from first response (CR or PR) to disease progression, or death from any cause, whichever occurs first.

Trial Locations

Locations (28)

Cancer Hospital Chinese Academy of Medical Sciences ( Site 2421); 🇨🇳 Beijing, Beijing, China

Peking Union Medical College Hospital ( Site 2425); 🇨🇳 Beijing, Beijing, China

Fujian Medical University Union Hospital ( Site 2410); 🇨🇳 Fuzhou, Fujian, China

Fujian Provincial Cancer Hospital ( Site 2414); 🇨🇳 Fuzhou, Fujian, China

900 Hospital of the Joint ( Site 2418); 🇨🇳 Fuzhou, Fujian, China

The First Affiliated Hospital of Xiamen University ( Site 2430); 🇨🇳 Xiamen, Fujian, China

Zhongshan Hospital Xiamen University ( Site 2447); 🇨🇳 Xiamen, Fujian, China

Guangdong General Hospital ( Site 2431); 🇨🇳 Guangzhou, Guangdong, China

Peking University Shenzhen Hospital ( Site 2442); 🇨🇳 Shenzhen, Guangdong, China

Harbin Medical University Cancer Hospital ( Site 2401); 🇨🇳 Harbin, Heilongjiang, China

Scroll for more (18 remaining)