Study of Atezolizumab Plus Carboplatin and Etoposide With or Without Tiragolumab in Participants With Untreated Extensive-Stage Small Cell Lung Cancer

PFS was defined as the time from randomization to the first occurrence of PD, as assessed by the investigator according to Response Evaluation Criteria in Solid Tumors, Version 1.1 (RECIST v1.1), or death from any cause, whichever occurred first in the PAS. PD was defined as at least a 20% increase in the sum of diameters (SOD) of target lesions, taking as reference the smallest SOD at prior timepoints (including baseline). Additionally, the sum must also demonstrate an absolute increase of ≥ 5 millimeters (mm) and unequivocal progression of existing non-target lesions. Kalpan-Meier (K-M) method was used to estimate median PFS.

OS was defined as the time from randomization to death from any cause in the PAS. K-M method was used to estimate median OS.

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

OS was defined as the time from randomization to death from any cause in the FAS. K-M method was used to estimate median OS.

ORR was defined as the percentage of participants with an objective response (OR), characterized by a confirmed complete response (CR) or partial response (PR) on two consecutive occasions ≥4 weeks apart, as assessed by the investigator according to RECIST v.1.1 in the PAS. CR was defined as the disappearance of all target and non-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. Percentages have been rounded off.

ORR was defined as the percentage of participants with an OR, characterized by a confirmed CR or PR on two consecutive occasions ≥4 weeks apart, as assessed by the investigator according to RECIST v.1.1 in the FAS. CR was defined as the disappearance of all target and non-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. Percentages have been rounded off.

DOR was defined as the time from the first occurrence of a documented OR to PD, as determined by the investigator according to RECIST v1.1 or death from any cause, whichever occurred first in the PAS. 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 and non-target lesions & normalization of tumor marker level. Additionally, any 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 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 the median DOR.

DOR was defined as the time from the first occurrence of a documented OR to PD, as determined by the investigator according to RECIST v1.1 or death from any cause, whichever occurred first in the FAS. 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 and non-target lesions & normalization of tumor marker level. Additionally, any 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 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 the median DOR.

PFS rate at 6 months and 12 months was defined as the percentage of participants who did not experience PD as determined by the investigator according to RECIST v1.1, or death from any cause at Months 6 and 12 in the PAS. PFS was defined as the time from randomization to the first occurrence of PD, as determined by the investigator according to RECIST v1.1, or death from any cause, whichever occurred first in the PAS. PD was defined as 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 the PFS rate. Percentages have been rounded off.

PFS rate at 6 months and 12 months was defined as the percentage of participants who did not experience PD, as determined by the investigator according to RECIST v1.1 or death from any cause, at Months 6 and 12 in the FAS. PFS was defined as the time from randomization to the first occurrence of PD, as determined by the investigator according to RECIST v1.1, or death from any cause, whichever occurred first in the FAS. PD was defined as 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 the PFS rate. Percentages have been rounded off.

OS rate at 12 months and 24 months was defined as the percentage of participants who did not experience death from any cause at the specified timepoints in the PAS. OS was defined as the time from randomization to death from any cause in the PAS. K-M method was used to estimate OS rate. Percentages have been rounded off.

OS rate at 12 months and 24 months was defined as the percentage of participants who did not experience death from any cause at the specified timepoints in the FAS. OS was defined as the time from randomization to death from any cause in the FAS. K-M method was used to estimate OS rate. Percentages have been rounded off.

TTCD=time from randomization to first confirmed clinically meaningful deterioration (CCMD) in PAS. EORTC QLQ-C30=cancer-specific instrument with 30 questions to evaluate 5 aspects of participant functioning (physical, emotional, role, cognitive, social), 3 symptom scales (fatigue, nausea, vomiting, pain), GHS/quality-of-life (QoL), & 6 single items (dyspnea, insomnia, appetite loss, constipation, diarrhea, financial difficulties). PF was scored on 4-point scale: 1=Not at all to 4=Very much. GHS/QoL was scored on 7-point scale: 1=Very poor to 7=Excellent. Scores were linearly transformed to range of 0-100. High score for PF or GHS/QoL scale=high/healthy level of functioning/better health-related quality-of-life (HRQoL). CCMD= ≥ 10-point decrease from baseline in PF or GHS scale score held for at least 2 consecutive assessments or an initial clinically meaningful decrease from baseline followed by death from any cause within 3 weeks. K-M method was used to estimate median TTCD.

TTCD was defined as time from randomization to first CCMD in FAS. EORTC QLQ-C30 is a cancer-specific instrument with 30 questions to evaluate 5 aspects of participant functioning (physical, emotional, role, cognitive, social), 3 symptom scales (fatigue, nausea, vomiting, pain), GHS/QoL, & 6 single items (dyspnea, insomnia, appetite loss, constipation, diarrhea, financial difficulties). PF was scored on 4-point scale: 1=Not at all to 4=Very much. GHS/QoL was scored on 7-point scale: 1=Very poor to 7=Excellent. Scores were linearly transformed to range of 0-100. High score for PF or GHS/QoL scale=high/healthy level of functioning/better HRQoL. CCMD was defined as ≥ 10-point decrease from baseline in PF or GHS scale score held for at least 2 consecutive assessments or an initial clinically meaningful decrease from baseline followed by death from any cause within 3 weeks. K-M method was used to estimate median TTCD.

An AE was defined as any untoward medical occurrence in a clinical investigation participant administered a pharmaceutical product, regardless of causal attribution. An AE was therefore any unfavorable and unintended sign (including an abnormal laboratory finding), symptom, or disease temporally associated with the use of a medicinal product, whether or not considered related to the medicinal product. 1 participant randomized to the tiragolumab arm did not receive any dose of tiragolumab and was moved to the placebo arm for safety analysis.

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.

Only sparse pharmacokinetic samples were collected in this study. With the focus on only Cmax and Cmin, there are no additional PK timepoints not reported.

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.