A Study of Atezolizumab Plus Tiragolumab in Combination With Paclitaxel and Cisplatin Compared With Paclitaxel and Cisplatin as First-Line Treatment in Participants With Unresectable Locally Advanced, Unresectable Recurrent, or Metastatic Esophageal Carcinoma

Investigator-assessed PFS

PFS was defined as the time from randomization to the first occurrence of PD or death from any cause (whichever occurred first), as determined by the investigator according to RECIST v1.1. PD was defined at least a 20% increase in the SOD of target lesions, taking as reference the smallest SOD at prior timepoints (including baseline). Additionally, the SOD must also demonstrate an absolute increase of ≥ 5 mm or unequivocal progression of existing non-target lesions. K-M method was used to estimate median PFS.

Time frame: From randomization to the first occurrence of PD or death from any cause, whichever occurs first (up to approximately 19 months)

IRF-assessed Confirmed Objective Response Rate (ORR)

IRF-assessed confirmed ORR was defined as the percentage of participants with an objective response (OR), characterized by a complete response (CR) or partial response (PR) on 2 consecutive occasions ≥ 4 weeks apart, as determined by an IRF according to RECIST v1.1. CR was defined as disappearance of all target lesions. \& normalization of tumor marker level. Additionally, any pathological lymph nodes (whether target or non-target) must have a reduction in short axis to \<10 mm. PR was defined as at least a 30% decrease in the SOD of all target lesions, taking as reference the baseline SOD, in the absence of CR.

Time frame: Up to approximately 19 months

Investigator-assessed Confirmed ORR

Investigator-assessed confirmed ORR was defined as the percentage of participants with an OR, characterized by a CR or a PR on 2 consecutive occasions ≥ 4 weeks apart, as determined by the investigator according to RECIST v1.1. CR was defined as disappearance of all target lesions. \& normalization of tumor marker level. Additionally, any pathological lymph nodes (whether target or non-target) must have a reduction in short axis to \<10 mm. PR was defined as at least a 30% decrease in the SOD of all target lesions, taking as reference the baseline SOD, in the absence of CR.

Time frame: Up to approximately 19 months

IRF-assessed Duration of Objective Response (DOR)

DOR was defined as the time from the first occurrence of a confirmed OR to PD or death from any cause (whichever occurred first), as determined by an IRF according to RECIST v1.1. OR was defined as either a CR or a PR on 2 consecutive occasions ≥ 4 weeks apart. CR was defined as disappearance of all target lesions. \& normalization of tumor marker level. Additionally, any pathological lymph nodes (whether target or non-target) must have a reduction in short axis to \<10 mm. PR was defined as at least a 30% decrease in the SOD of all target lesions, taking as reference the baseline SOD, in the absence of CR. PD was defined as at least a 20% increase in the SOD of target lesions, taking as reference the smallest SOD on study (including baseline). Additionally, the SOD must also demonstrate an absolute increase of ≥ 5 mm or unequivocal progression of existing non-target lesions. K-M method was used to estimate median DOR.

Time frame: From the first occurrence of a of a confirmed OR to PD or death from any cause, whichever occurred first (up to approximately 19 months)

Investigator-assessed DOR

DOR was defined as the time from the first occurrence of a confirmed OR to PD or death from any cause (whichever occurred first), as determined by an IRF according to RECIST v1.1. OR was defined as either a CR or a PR on 2 consecutive occasions ≥ 4 weeks apart. CR was defined as disappearance of all target lesions. \& normalization of tumor marker level. Additionally, any pathological lymph nodes (whether target or non-target) must have a reduction in short axis to \<10 mm. PR was defined as at least a 30% decrease in the SOD of all target lesions, taking as reference the baseline SOD, in the absence of CR. PD was defined as at least a 20% increase in the SOD of target lesions, taking as reference the smallest SOD on study (including baseline). Additionally, the SOD must also demonstrate an absolute increase of ≥ 5 mm or unequivocal progression of existing non-target lesions. K-M method was used to estimate median DOR.

Time frame: From the first occurrence of a of a confirmed OR to PD or death from any cause, whichever occurred first (up to approximately 19 months)

Time to Confirmed Deterioration (TTCD) in Participant-reported Physical Functioning, as Measured by European Organisation for Research and Treatment of Cancer Quality of Life Questionnaire - Core 30 (EORTC QLQ-C30)

Clinically meaningful changes in physical functioning as measured by the EORTC QLQ-C30. EORTC QLQ-C30 is a self-reported measure, consisting of 30 questions that assess 5 aspects of participants functioning (physical, emotional, role, cognitive and social), 3 symptom scales (fatigue, nausea and vomiting, and pain), global health status/quality of life (GHS/QoL), and 6 single items (dyspnea, insomnia, appetite loss, constipation, diarrhea and financial difficulties) within the previous week. Physical functioning was scored on a 4-point scale: 1=Not at all, 2=A little, 3=Quite a bit, 4=Very much. Scores were linearly transformed to a range of 0 to 100, with higher scores (i.e. closer to 100) reflecting better functioning. Participants were considered "Worsened" if their baseline score decreased by ≥10 points. K-M method was used to estimate median TTCD.

Time frame: Up to approximately 27 months

TTCD in Participant-reported Role Functioning (RF), as Measured by EORTC QLQ-C30

Clinically meaningful changes in role functioning as measured by the EORTC QLQ-C30. EORTC QLQ-C30 is a self-reported measure, consisting of 30 questions that assess 5 aspects of participants functioning (physical, emotional, role, cognitive and social), 3 symptom scales (fatigue, nausea and vomiting, and pain), GHS/QoL, and 6 single items (dyspnea, insomnia, appetite loss, constipation, diarrhea and financial difficulties) within the previous week. Role functioning was scored on a 4-point scale: 1=Not at all, 2=A little, 3=Quite a bit, 4=Very much. Scores were linearly transformed to a range of 0 to 100, with higher scores (i.e. closer to 100) reflecting better functioning. Participants were considered "Worsened" if their baseline score decreased by ≥10 points. K-M method was used to estimate median TTCD.

Time frame: Up to approximately 27 months

TTCD in Participant-Reported GHS/QoL, as Measured by EORTC QLQ-C30

Clinically meaningful changes in GHS/QoL as measured by the EORTC QLQ-C30. EORTC QLQ-C30 is a self-reported measure, consisting of 30 questions that assess 5 aspects of participants functioning (physical, emotional, role, cognitive and social), 3 symptom scales (fatigue, nausea and vomiting, and pain), GHS/QoL, and 6 single items (dyspnea, insomnia, appetite loss, constipation, diarrhea and financial difficulties) within the previous week. GHS and QoL items were scored on a 7-point scale, with scores ranging from 1=Very poor to 7=Excellent. Scores were linearly transformed to a range of 0 to 100, with higher scores (i.e. closer to 100) reflecting better GHS/QoL. Participants were considered "Worsened" if their baseline score decreased by ≥10 points. K-M method was used to estimate median TTCD.

Time frame: Up to approximately 27 months

TTCD in Participant-reported Dysphagia, as Measured by European Organisation for Research and Treatment of Cancer Quality-of-life Esophageal Cancer, Module 18 Questionnaire (EORTC QLQ-OES18)

Clinically meaningful changes in dysphagia as measured by the EORTC QLQ-OES18. EORTC QLQ-OES18 is a modular supplement to the EORTC QLQ-C30 questionnaire for use in participants with esophageal cancer. EORTC QLQ-OES18 consists of 4 multiple-item scale (dysphagia, eating, reflux, and pain) and 6 single items (trouble swallowing saliva, choked when swallowing, dry mouth, trouble with taste, trouble with coughing, and trouble talking) with a recall period of the previous week. Each symptom item was scored on a 4-point scale: 1=Not at all, 2=A little, 3=Quite a bit, 4=Very much. Scores were linearly transformed to a range of 0 to 100, with higher transformed scores (i.e. closer to 100) reflecting worse symptoms. Participants were considered "Worsened" if their baseline score increased by ≥ 10 points. K-M method was used to estimate median TTCD.

Time frame: Up to approximately 27 months

Number of Participants With Adverse Events (AEs)

An AE was any untoward medical occurrence in a participant administered a pharmaceutical product, and which does not necessarily have a causal relationship with the treatment. An AE was therefore any unfavorable and unintended sign (including an abnormal laboratory finding, for example), symptom, or disease temporally associated with the use of a pharmaceutical product, whether or not considered related to the pharmaceutical product.

Time frame: Up to approximately 49.6 months

Number of Participants With Cytokine-release Syndrome (CRS), With Severity Determined by the American Society for Transplantation and Cell Therapy (ASTCT) Consensus Grading Scale

CRS was defined as supraphysiologic response following administration of any immune therapy that results in activation/engagement of endogenous or infused T cells and/or other immune effector cells. Symptoms may be progressive, including fever at onset, and may also include hypotension, capillary leak (hypoxia), and end-organ dysfunction. Severity of CRS was determined per ASTCT Consensus Grading Criteria, which categorizes CRS into 5 grades: Grade 1: fever (≥38◦Celsius), with/without constitutional symptoms, in absence of hypotension \& hypoxia; Grade 2: fever with hypotension not requiring vasopressors and/or hypoxia requiring low-flow oxygen; Grade 3: fever with hypotension requiring one vasopressor, with/without vasopressin, and/or hypoxia requiring high-flow oxygen; Grade 4: fever accompanied by hypotension requiring multiple vasopressors (excluding vasopressin) and/or hypoxia requiring positive-pressure ventilation; Grade 5: death due to CRS.

Time frame: Up to approximately 49.6 months

Minimum Serum Concentration (Cmin) of Tiragolumab

Time frame: Pre-dose on Day 1 of Cycles 2, 3, 4, 8, 12, and 16 (1 Cycle=21 days)

Maximum Serum Concentration (Cmax) of Tiragolumab

Time frame: 30 minutes post-dose on Day 1 of Cycle 1 (1 Cycle=21 days)

Cmin of Atezolizumab

Time frame: Pre-dose on Day 1 of Cycles 2, 3, 4, 8, 12, and 16 (1 Cycle=21 days)

Cmax of Atezolizumab

Time frame: 30 minutes post-dose on Day 1 of Cycle 1 (1 Cycle=21 days)

Number of Participants With Anti-drug Antibodies (ADAs) to Tiragolumab

Participants were considered to be ADA positive if they were ADA negative at baseline but developed an ADA response following tiragolumab administration (treatment-induced ADA response), or if they were ADA positive at baseline and the titer of one or more post-baseline samples was greater than the titer of the baseline sample by a scientifically reasonable margin such as at least 0.60 titer unit (t.u.) greater than the baseline titer result (treatment-enhanced ADA response). Participants with a positive post-baseline sample have been reported here.

Time frame: Up to approximately 27.5 months

Number of Participants With ADAs to Atezolizumab

Participants were considered to be ADA positive if they were ADA negative at baseline but developed an ADA response following atezolizumab administration (treatment-induced ADA response), or if they were ADA positive at baseline and the titer of one or more post-baseline samples was greater than the titer of the baseline sample by a scientifically reasonable margin such as at least 0.60 t.u. greater than the baseline titer result (treatment-enhanced ADA response). Participants with a positive post-baseline sample have been reported here.

Time frame: Up to approximately 27.5 months