PFS was defined as time from randomization until the date of radiographic disease progression based on investigator assessment using Response Evaluation Criteria in Solid Tumors (RECIST) version 1.1 or death from any cause, whichever came first. PFS was analyzed using Kaplan-Meier methods. Participants with no progression or death, or who started new anticancer therapy before documented progression or death without documented progression, or who had ≥ 2 consecutive missing tumor assessments before documented progression or death without documented progression were censored on the date of last adequate tumor assessment. Participants with no baseline tumor assessment, were censored at the date of randomization.

The primary efficacy analysis was pre-specified to be conducted after at least 84 PFS events were observed.

Intent-to-treat population

OS is defined as time from randomization until death from any cause. Participants who were lost to follow-up or did not have a date of death were censored at the last date that they were known to be alive. Participants with confirmed death or alive status after the data cutoff date were censored at the data cutoff date. Median OS was estimated using a Kaplan-Meier analysis.

Intent-to-treat population

Tumor response assessment was performed by the investigator per Response Evaluation Criteria in Solid Tumors (RECIST) v1.1 guidelines. ORR is defined as the percentage of participants who achieved a best overall response (BOR) of either complete response (CR) or partial response (PR) based on investigator assessment of tumor lesions per RECIST v1.1.

CR was defined as the disappearance of all lesions except lymph node short axis < 10 mm; PR was defined as a ≥ 30% reduction in sum of diameters in target lesions.

Intent-to-treat population

TEAEs are defined as adverse events (AEs) that started or worsened from the start of study drug to 28 days after permanent discontinuation of study drug.

A serious AE is defined as any untoward medical occurrence that:

• Resulted in death;
• Was life-threatening;
• Required inpatient hospitalization or prolongation of existing hospitalization;
• Resulted in persistent or significant disability or incapacity;
• Was a congenital anomaly or birth defect.

The investigator assessed the causality/relationship between study treatment and each AE, and assessed the severity of each AE according to the National Cancer Institute Common Toxicity Criteria for Adverse Events (NCI-CTCAE), version 5.0 on a scale from mild (Grade 1), moderate (Grade 2), severe (Grade 3), life-threatening (Grade 4), or death due to the AE (Grade 5). Cornea and retina AEs were defined by Standardized Medical Dictionary for Regulatory Activities Queries (SMQs) of corneal disorders and retinal disorders (broad).

Safety population includes all participants who received any portion of at least 1 dose of study treatment (bemarituzumab + mFOLFOX6 or placebo + mFOLFOX6).

OS is defined as time from randomization until death from any cause. Participants who were lost to follow-up or did not have a date of death were censored at the last date that they were known to be alive. Median OS was estimated using a Kaplan-Meier analysis.

Intent-to-treat population