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

PFS was defined as the time from randomization to the first documented PD as determined by the investigator with the use of Response Evaluation Criteria in Solid Tumors Version 1.1 (RECIST v1.1) or death from any cause, whichever occurred first. PD was defined as at least a 20% increase in the sum of diameters (SOD) of target lesions, taking as reference the smallest SOD on study (including baseline). In addition to the relative increase of 20%, the SOD must also demonstrate an absolute increase of ≥ 5 millimeters (mm).

OS was defined as the time from randomization to death from any cause.

PFS was defined as the time from randomization to the first documented PD as determined by the investigator with the use of RECIST v1.1 or death from any cause, whichever occurred first. 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). In addition to the relative increase of 20%, the SOD must also demonstrate an absolute increase of ≥ 5 mm.

OS was defined as the time from randomization to death from any cause.

ORR was defined as the percentage of participants with a complete response (CR) or a partial response (PR) as determined by the investigator with the use of RECIST v1.1. CR was defined as disappearance of all target lesions or any pathological lymph nodes (whether target or non-target) must have 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 CR or PR as determined by the investigator with the use of RECIST v1.1. CR was defined as disappearance of all target lesions or any pathological lymph nodes (whether target or non-target) must have 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 (CR or PR) to PD or death from any cause, whichever occurred first, as determined by the investigator with the use of RECIST v1.1. CR was defined as disappearance of all target lesions or any pathological lymph nodes (whether target or non-target) must have 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). In addition to the relative increase of 20%, the SOD must also demonstrate an absolute increase of ≥ 5 mm.

DOR was defined as the time from the first occurrence of a documented OR (CR or PR) to PD or death from any cause, whichever occurred first, as determined by the investigator with the use of RECIST v1.1. CR was defined as disappearance of all target lesions or any pathological lymph nodes (whether target or non-target) must have 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). In addition to the relative increase of 20%, the SOD must also demonstrate an absolute increase of ≥ 5 mm.

PFS rate at 6 months and 12 months was defined as the percentage of participants who were event-free at these specific time points. Percentages have been rounded off to the nearest decimal point. A point estimate of the event-free rate was a single, numerical value used to approximate the true event-free rate of the entire population at a specific point in time. This value was calculated from ordered data (Event, Censoring) of each participant, using the Kaplan-Meier (K-M) method, accounting for censored observations (so event-free rates may not directly be calculated based only on participants remaining at risk).

PFS rate at 6 months and 12 months was defined as the percentage of participants who were event-free at these specific time points. Percentages have been rounded off to the nearest decimal point. A point estimate of the event-free rate was a single, numerical value used to approximate the true event-free rate of the entire population at a specific point in time. This value was calculated from ordered data (Event, Censoring) of each participant, using the K-M method, accounting for censored observations (so event-free rates may not directly be calculated based only on participants remaining at risk).

OS rate at 12 months and 24 months was defined as the percentage of participants who were alive at these specific time points. Percentages have been rounded off to the nearest decimal point. A point estimate of the event-free rate was a single, numerical value used to approximate the true event-free rate of the entire population at a specific point in time. This value was calculated from ordered data (Event, Censoring) of each participant, using the K-M method, accounting for censored observations (so event-free rates may not directly be calculated based only on participants remaining at risk).

OS rate at 12 months and 24 months was defined as the percentage of participants who were alive at these specific time points. Percentages have been rounded off to the nearest decimal point. A point estimate of the event-free rate was a single, numerical value used to approximate the true event-free rate of the entire population at a specific point in time. This value was calculated from ordered data (Event, Censoring) of each participant, using the K-M method, accounting for censored observations (so event-free rates may not directly be calculated based only on participants remaining at risk).

TTCD was the time from randomization until the first confirmed clinically meaningful deterioration in PF. TTCD was determined based on patient-reported PF (Items 1-5) as collected and measured by the EORTC QLQ-C30. The PF was measured on 4-point scale (1='Not at all' to 4='Very much'). A high score for the PF subscale represented a high/healthy level of functioning. The scale was linearly transformed so that each score ranged from 0 to 100. A score change of at least 10-point in PF subscale score was perceived by participants as clinically meaningful. Confirmed clinically meaningful deterioration was defined as a clinically meaningful decrease from baseline that was held for at least two consecutive assessments or an initial clinically meaningful decrease from baseline followed by death from any cause within 3 weeks.

TTCD was the time from randomization until the first confirmed clinically meaningful deterioration in PF. TTCD was determined based on patient-reported PF (Items 1-5) as collected and measured by the EORTC QLQ-C30. The PF was measured on 4-point scale (1='Not at all' to 4='Very much'). A high score for the PF subscale represented a high/healthy level of functioning. The scale was linearly transformed so that each score ranged from 0 to 100. A score change of at least 10-point in PF subscale score was perceived by participants as clinically meaningful. Confirmed clinically meaningful deterioration was defined as a clinically meaningful decrease from baseline that was held for at least two consecutive assessments or an initial clinically meaningful decrease from baseline followed by death from any cause within 3 weeks.

TTCD was the time from randomization until the first confirmed clinically meaningful deterioration in patient-reported GHS/QoL. TTCD was determined based on patient-reported GHS/QoL (Items 29-30) as collected and measured by the EORTC QLQ-C30. GHS/QoL items were scored on a 7-point scale, ranging from "very poor" to "excellent". A high score for the GHS/QoL subscale represented a high health-related QoL. The scale was linearly transformed so that each score ranged from 0 to 100. A score change of at least 10-point in GHS/QoL subscale score was perceived by participants as clinically meaningful. Confirmed clinically meaningful deterioration was defined as a clinically meaningful decrease from baseline that was held for at least two consecutive assessments or an initial clinically meaningful decrease from baseline followed by death from any cause within 3 weeks.

TTCD was the time from randomization until the first confirmed clinically meaningful deterioration in patient-reported GHS/QoL. TTCD was determined based on patient-reported GHS/QoL (Items 29-30) as collected and measured by the EORTC QLQ-C30. GHS/QoL items were scored on a 7-point scale, ranging from "very poor" to "excellent". A high score for the GHS/QoL subscale represented a high health-related QoL. The scale was linearly transformed so that each score ranged from 0 to 100. A score change of at least 10-point in GHS/QoL subscale score was perceived by participants as clinically meaningful. Confirmed clinically meaningful deterioration was defined as a clinically meaningful decrease from baseline that was held for at least two consecutive assessments or an initial clinically meaningful decrease from baseline followed by death from any cause within 3 weeks.

An AE was defined as any untoward medical occurrence in a participant administered a pharmaceutical product and which does not necessarily have to have a causal relationship with the treatment. An adverse event can therefore be 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. Pre-existing conditions which worsen during a study were also considered as AEs.

CRS=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 non zero values have been 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 at least 0.60 titer unit (t.u.) greater than the baseline titer result (treatment-enhanced ADA response). The total number of participants who developed ADAs to tiragolumab was determined by summing the ADA-positive participants across all timepoints.

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 at least 0.60 t.u. greater than the baseline titer result (treatment-enhanced ADA response). The total number of participants who developed ADAs to tiragolumab was determined by summing the ADA-positive participants across all timepoints.

The EQ-5D-5L is a validated self-report health status questionnaire that was used to calculate a health status utility score for use in health economic analyses. There were two components to the EQ-5D-5L: a five-item health state profile that assessed mobility, self-care, usual activities, pain/discomfort, and anxiety/depression, as well as a visual analog scale (VAS) that measured health state. The EQ VAS records the participant's self-rated health on a vertical visual analogue scale ranging from 0 to 100. A single composite score was calculated based on the responses as an indicator of the participant's health status. The scale ranges 0-100, 0=worst health and 100=best health.