Tislelizumab in Combination With Chemotherapy as First-Line Treatment in Adults With Inoperable, Locally Advanced or Metastatic Gastric, or Gastroesophageal Junction Carcinoma

Progression-free survival is defined as the time from the date of randomization to the date of the first objectively documented tumor progression assessed by the investigator according to Response Evaluation Criteria in Solid Tumors (RECIST) version 1.1, or death, whichever occurred first.

Median PFS was estimated using the Kaplan-Meier method.

ORR is defined as the percentage of participants whose best overall response is complete response (CR) or partial response (PR) per Response Evaluation Criteria in Solid Tumors v1.1 assessed by the investigator.

Investigators conducted assessments of radiological tumor response by computed tomography (CT) or magnetic resonance imaging (MRI) per RECIST version 1.1 about every six weeks during the first 48 weeks of the study and every nine weeks thereafter.

CR: Disappearance of all target and non-target lesions and no new lesions. Any pathological lymph nodes must have reduction in short axis to < 10 mm.

PR: At least a 30% decrease in the sum of diameters of target lesions, taking as reference the baseline sum diameters, persistence of one or more nontarget lesion(s) and/or maintenance of tumor marker level above the normal limits.

Progression-free survival is defined as the time from the date of randomization to the date of the first objectively documented tumor progression assessed by the investigator according to Response Evaluation Criteria in Solid Tumors (RECIST) version 1.1, or death, whichever occurred first.

Median PFS was estimated using the Kaplan-Meier method.

ORR is defined as the percentage of participants whose best overall response is complete response (CR) or partial response (PR) per Response Evaluation Criteria in Solid Tumors v1.1 assessed by the investigator.

Investigators conducted assessments of radiological tumor response by computed tomography (CT) or magnetic resonance imaging (MRI) per RECIST version 1.1 about every six weeks during the first 48 weeks of the study and every nine weeks thereafter.

CR: Disappearance of all target and non-target lesions and no new lesions. Any pathological lymph nodes must have reduction in short axis to < 10 mm.

PR: At least a 30% decrease in the sum of diameters of target lesions, taking as reference the baseline sum diameters, persistence of one or more nontarget lesion(s) and/or maintenance of tumor marker level above the normal limits.

DOR is defined as the time from the first determination of an objective response assessed by the investigator per RECIST v1.1, until the first documentation of progression or death, whichever occurred first.

Progressive disease (PD): At least a 20% increase in the size of target lesions, taking as reference the smallest size on study, with an absolute increase of at least 5 mm, unequivocal progression of existing non-target lesions, or any new lesions.

DOR is defined as the time from the first determination of an objective response assessed by the investigator per RECIST v1.1, until the first documentation of progression or death, whichever occurred first.

Progressive disease (PD): At least a 20% increase in the size of target lesions, taking as reference the smallest size on study, with an absolute increase of at least 5 mm, unequivocal progression of existing non-target lesions, or any new lesions.

The EORTC QLQ-30 contains 30 questions that incorporate 5 functional scales (physical functioning, role functioning, emotional functioning, cognitive functioning, and social functioning), 1 global health status scale, 3 symptom scales (fatigue, nausea and vomiting, and pain), and 6 single items (dyspnea, insomnia, appetite loss, constipation, diarrhea, and financial difficulties). The participant answers questions about their health during the past week. There are 28 questions answered on a 4-point scale where 1 = Not at all (best) and 4 = Very Much (worst) and 2 global health quality of life (QOL) questions answered on a 7-point scale where 1 = Very poor and 7 = Excellent. Raw scores are transformed to a 0 to 100 scale via linear transformation. Higher scores in GHS and functional scales indicate better quality of life.

The EORTC QLQ-30 contains 30 questions that incorporate 5 functional scales (physical functioning, role functioning, emotional functioning, cognitive functioning, and social functioning), 1 global health status scale, 3 symptom scales (fatigue, nausea and vomiting, and pain), and 6 single items (dyspnea, insomnia, appetite loss, constipation, diarrhea, and financial difficulties). The participant answers questions about their health during the past week. There are 28 questions answered on a 4-point scale where 1 = Not at all (best) and 4 = Very Much (worst) and 2 global health quality of life (QOL) questions answered on a 7-point scale where 1 = Very poor and 7 = Excellent. Raw scores are transformed to a 0 to 100 scale via linear transformation. The fatigue symptom scale includes 3 items and ranges from 0 to 100, where higher scores indicate a higher level of symptoms.

EORTC-QLQ-STO22 is a 22-item questionnaire developed to assess QoL of gastric cancer participants. It consists of 5 multi-item subscales: Dysphagia/odynophagia (4 items), Pain/discomfort (3 items), Dietary restrictions (5 items), Upper gastro-intestinal (GI) symptoms (3 items), Specific emotional problems (3 items) and 4 single items. Each question is answered on a scale from 0 (Not at all) to 4 (Very Much), where lower scores indicate fewer symptoms/better QoL.

Raw scores were transformed to a scale from 0 to 100, where lower scores indicate better QoL.

The QLQ-STO22 Index score is the mean of the 6 domain scores and 4 single items.

The EQ-5D-5L measures health outcomes using a VAS to record a participant's self-rated health on a scale from 0 to 100, where 100 is 'the best health you can imagine' and 0 is 'the worst health you can imagine.' A higher score indicates better health outcomes.

An AE is defined as any unfavorable and unintended sign (including an abnormal laboratory finding), symptom, or disease (new or exacerbated) temporally associated with the use of study drugs, whether related to study drugs or not.

An SAE is any untoward medical occurrence that, at any dose met any of the following criteria:

• Resulted in death
• Was life-threatening
• Required hospitalization or prolongation of existing hospitalization
• Resulted in disability/incapacity
• Was a congenital anomaly/birth defect
• Was considered a significant medical AE by the Investigator based on medical judgement.

Disease Control Rate is defined as the percentage of participants who had confirmed CR, PR, or stable disease (SD) assessed by the investigator and the investigator per RECIST v1.1. Investigators conducted assessments of radiological tumor response by CT or MRI per RECIST version 1.1 about every six weeks during the first 48 weeks of the study and every nine weeks thereafter.

CR: Disappearance of all target and non-target lesions and no new lesions. Any pathological lymph nodes must have reduction in short axis to < 10 mm.

PR: At least a 30% decrease in the sum of diameters of target lesions, taking as reference the baseline sum diameters, persistence of one or more nontarget lesion(s) and/or maintenance of tumor marker level above the normal limits.

SD: Neither sufficient shrinkage in size of lesions to qualify for PR nor sufficient increase to qualify for PD, and no new lesions.

Disease Control Rate is defined as the percentage of participants who had confirmed CR, PR, or stable disease (SD) assessed by the investigator per RECIST v1.1. Investigators conducted assessments of radiological tumor response by CT or MRI per RECIST version 1.1 about every six weeks during the first 48 weeks of the study and every nine weeks thereafter.

CR: Disappearance of all target and non-target lesions and no new lesions. Any pathological lymph nodes must have reduction in short axis to < 10 mm.

PR: At least a 30% decrease in the sum of diameters of target lesions, taking as reference the baseline sum diameters, persistence of one or more nontarget lesion(s) and/or maintenance of tumor marker level above the normal limits.

SD: Neither sufficient shrinkage in size of lesions to qualify for PR nor sufficient increase to qualify for PD, and no new lesions.

Clinical benefit rate is defined as the percentage of participants who achieved a confirmed complete response, partial response, or durable stable disease assessed by the Investigator per RECIST v1.1.

CR: Disappearance of all target and non-target lesions and no new lesions. Any pathological lymph nodes must have reduction in short axis to < 10 mm.

PR: At least a 30% decrease in the sum of diameters of target lesions, taking as reference the baseline sum diameters, persistence of one or more nontarget lesion(s) and/or maintenance of tumor marker level above the normal limits.

Durable SD: Stable disease for ≥ 24 weeks.

Clinical benefit rate is defined as the percentage of participants who achieved a confirmed complete response, partial response, or durable stable disease assessed by the Investigator per RECIST v1.1.

CR: Disappearance of all target and non-target lesions and no new lesions. Any pathological lymph nodes must have reduction in short axis to < 10 mm.

PR: At least a 30% decrease in the sum of diameters of target lesions, taking as reference the baseline sum diameters, persistence of one or more nontarget lesion(s) and/or maintenance of tumor marker level above the normal limits.

Durable SD: Stable disease for ≥ 24 weeks.

Time to response is defined as the time from randomization to the first determination of an objective response per RECIST version 1.1 as assessed by the investigator.

Time to response is defined as the time from randomization to the first determination of an objective response per RECIST version 1.1 as assessed by the investigator.