A Study to Evaluate the Efficacy and Safety of ONO-4538 in Combination With Ipilimumab and Chemotherapy in Chemotherapy-naïve Participants With HER2-negative Unresectable Advanced or Recurrent Gastric Cancer (Including Esophagogastric Junction Cancer)

Study Overview
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Brief Summary
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This study is to compare and evaluate the efficacy and safety of ONO-4538 in combination with ipilimumab and chemotherapy versus chemotherapy in chemotherapy-naïve participants with HER2-negative unresectable advanced or recurrent gastric cancer (including esophagogastric junction cancer).

Official Title
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A Randomized, Multicenter, Open-label, Phase III Study to Compare the Efficacy and Safety of ONO-4538 in Combination With Ipilimumab, Fluoropyrimidine-based and Platinum-based Chemotherapy (Hereinafter Referred to as Chemotherapy) Versus Chemotherapy in Chemotherapy-naïve Participants With Human Epidermal Growth Factor Receptor 2 (HER2)-Negative Unresectable Advanced or Recurrent Gastric Cancer (Including Esophagogastric Junction Cancer)

Conditions
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Gastric Cancer

Intervention / Treatment
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* Drug: ONO-4538
* Drug: Ipilimumab
* Drug: Oxaliplatin
* Drug: Capecitabine
* Drug: S-1


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Participants with unresectable advanced or recurrent gastric cancer (including esophagogastric junction cancer) that has been histologically confirmed to be predominant adenocarcinoma Eastern Cooperative Oncology Group (ECOG) Performance Status (PS) score 0 or 1 Participants who have a life expectancy of at least 3 months Exclusion Criteria: Participants with a history or complications of multiple cancers Participants with a complication or history of severe hypersensitivity to any other antibody products Participants with concurrent autoimmune disease or a history of chronic or recurrent autoimmune disease.

Ages Eligible for Study
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Minimum Age: 20 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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No

Study Plan
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How is the study designed?
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Design Details

Primary Purpose: Treatment
Allocation: Randomized
Intervention Model: Parallel Assignment
Masking: None (Open Label)


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: ONO-4538 + ipilimumab + chemotherapy<br> | Drug: ONO-4538<br>* Specified dose on specified days<br>* Other names: Opdivo;Drug: Ipilimumab<br>* Specified dose on specified days<br>* Other names: Yervoy;Drug: Oxaliplatin<br>* Specified dose on specified days<br>Drug: Capecitabine<br>* Specified dose on specified days<br>Drug: S-1<br>* Specified dose on specified days<br>* Other names: Tegafur-gimeracil-oteracil potassium;|
| Active Comparator: Chemotherapy<br> | Drug: Oxaliplatin<br>* Specified dose on specified days<br>Drug: Capecitabine<br>* Specified dose on specified days<br>Drug: S-1<br>* Specified dose on specified days<br>* Other names: Tegafur-gimeracil-oteracil potassium;|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Overall survival (OS) |  | up to 3 years | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Progression-free survival (PFS) (site investigator assessment) |  | up to 3 years | 
| Objective response rate (ORR) (site investigator assessment) |  | up to 3 years | 
| Best overall response (BOR) (site investigator assessment) |  | up to 3 years | 
| Duration of response (DOR) (site investigator assessment) |  | up to 3 years | 
| Disease control rate (DCR) (site investigator assessment) |  | up to 3 years | 
| Time to response (TTR) (site investigator assessment) |  | up to 3 years | 
| Maximum percent change in the sum diameters of the target lesions (site investigator assessment) |  | up to 3 years | 
| Progression-free survival after the next line of therapy (PFS2) (site investigator assessment) |  | up to 3 years | 
| Adverse event |  | Up to 30 days after the last dose |