PFS was defined as the time from randomization to the date of first documented PD as determined by the IRF according to Response Evaluation Criteria in Solid Tumors Version 1.1 (RECIST v1.1) or death, whichever occurs first. PD was defined as appearance of a new lesion(s), unequivocal progression in non-target lesion(s) or at least a 20% increase in the sum of diameters (SOD) of target lesions, taking as reference the smallest sum on the study including baseline (nadir). In addition to the relative increase of 20%, the sum must also demonstrate an absolute increase of at least 5 millimetres (mm).

FAS included all participants randomized into the randomized phase, regardless of whether or not the assigned study treatment was received.

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

FAS included all participants randomized into the randomized phase, regardless of whether or not the assigned study treatment was received.

PFS was defined as the time from randomization to the date of first documented PD as assessed by investigator according to RECIST v1.1 or death, whichever occurs first. PD was defined as appearance of a new lesion(s), unequivocal progression in non-target lesion(s) or at least a 20% increase in the SOD of target lesions, taking as reference the smallest sum on the study including baseline (nadir). In addition to the relative increase of 20%, the sum must also demonstrate an absolute increase of at least 5 mm.

FAS included all participants randomized into the randomized phase, regardless of whether or not the assigned study treatment was received.

ORR was defined as the percentage of participants with an objective tumor response of complete response (CR) or partial response (PR) as determined by the IRF using RECIST v.1.1. CR was defined as the disappearance of all target and non-target lesions or any pathological lymph nodes (whether target or non-target) have a reduction in short axis to < 10 mm. PR was defined as at least a 30% decrease in the sum of diameters (SOD) of target lesions, taking as reference the baseline SOD. Percentages have been rounded off.

FAS included all participants randomized into the randomized phase, regardless of whether or not the assigned study treatment was received. Overall number analyzed is the number of participants with measurable disease at baseline, as assessed by IRF.

ORR was defined as the percentage of participants with an objective tumor response of CR or PR as determined by the investigator using RECIST v.1.1. CR was defined as the disappearance of all target and non-target lesions. Any pathological lymph nodes (whether target or non-target) have a reduction in short axis to < 10 mm. PR was defined as at least a 30% decrease in the SOD of target lesions, taking as reference the baseline SOD.

FAS included all participants randomized into the randomized phase, regardless of whether or not the assigned study treatment was received. Overall number analyzed is the number of participants with measurable disease at baseline, as assessed by investigator.

DOR was calculated for participants who had a best confirmed OR of CR/PR. DOR= time from first occurrence of a documented OR until the time of documented PD as determined by IRF assessment using RECIST v1.1 or death from any cause, whichever occurs first. CR=disappearance of all target and non-target lesions or any pathological lymph nodes (whether target or non-target) having a reduction in short axis to <10 mm. PR= at least a 30% decrease in the SOD of target lesions, taking as reference the baseline SOD. PD was defined as appearance of a new lesion(s), unequivocal progression in non-target lesion(s) or at least a 20% increase in the SOD of target lesions, taking as reference the smallest sum on the study including baseline (nadir). In addition to the relative increase of 20%, the sum must also demonstrate an absolute increase of at least 5 mm.

FAS included all participants randomized into the randomized phase, regardless of whether or not the assigned study treatment was received. Overall number analyzed is the number of participants with response, per IRF.

DOR was calculated for participants who had a best confirmed OR of CR/PR. DOR= time from first occurrence of a documented OR until the time of documented PD as determined by investigator using RECIST v1.1 or death from any cause, whichever occurs first. CR=disappearance of all target and non-target lesions or any pathological lymph nodes (whether target or non-target) having a reduction in short axis to <10 mm. PR= at least a 30% decrease in the SOD of target lesions, taking as reference the baseline SOD. PD was defined as appearance of a new lesion(s), unequivocal progression in non-target lesion(s) or at least a 20% increase in the SOD of target lesions, taking as reference the smallest sum on the study including baseline (nadir). In addition to the relative increase of 20%, the sum must also demonstrate an absolute increase of at least 5 mm.

FAS included all participants randomized into the randomized phase, regardless of whether or not the assigned study treatment was received. Overall number analyzed is the number of participants with response, per investigator.

PFS rate at 6 months and 12 months was defined as the percentage of participants who had not experienced PD as determined by the IRF according to RECIST v1.1 or death from any cause at 6 months and 12 months after randomization. PD was defined as appearance of a new lesion(s), unequivocal progression in non-target lesion(s) or at least a 20% increase in the SOD of target lesions, taking as reference the smallest sum on the study including baseline (nadir). In addition to the relative increase of 20%, the sum must also demonstrate an absolute increase of at least 5 mm. Percentages have been rounded off.

FAS included all participants randomized into the randomized phase, regardless of whether or not the assigned study treatment was received.

PFS rate at 6 months and 12 months was defined as the percentage of participants who had not experienced PD as determined by the investigator according to RECIST v1.1 or death from any cause at 6 months and 12 months after randomization. PD was defined as appearance of a new lesion(s), unequivocal progression in non-target lesion(s) or at least a 20% increase in the SOD of target lesions, taking as reference the smallest sum on the study including baseline (nadir). In addition to the relative increase of 20%, the sum must also demonstrate an absolute increase of at least 5 mm. Percentages have been rounded off.

FAS included all participants randomized into the randomized phase, regardless of whether or not the assigned study treatment was received.

OS rate at 12 months and 24 months was defined as the percentage of participants who had not experienced death from any cause at 12 months and 24 months after randomization. Percentages have been rounded off.

An AE =any unfavorable & unintended sign (including abnormal laboratory values/abnormal clinical test results), symptoms/disease temporally associated with the use of a pharmaceutical product, whether considered related to the pharmaceutical product. SAE=any significant hazard, contraindication, side effect that is fatal or life-threatening, requires hospitalization or prolongation of existing hospitalization, results in persistent or significant disability/incapacity, is a congenital anomaly/birth defect, is medically significant or requires intervention to prevent one or other of the outcomes listed above. AESI= drug induced liver injury, suspected transmission of infectious agent via study treatment, hepatitis, systemic lupus erythematosus, hypersensitivity, etc. AESIs may include events not specified in the protocol.

Saftey analysis set (SAS)=all participants who were randomized & received at least 1 dose of atezolizumab/lurbinectedin.

For determining post-baseline incidence, participants were considered to be ADA-positive if they were ADA-negative or had missing data at baseline but developed at least one positive post-baseline ADA result during the randomized phase, or if they were ADA-positive at baseline and the titer of 1 or more post-baseline samples was at least 0.60 titer units (t.u.) greater than the baseline titer result.

ADA-evaluable population was defined as participants with at least one post-dose evaluable ADA sample (collected in the randomized phase).

EORTC QLQ-C30=30 questions assessing 5 aspects of participant functioning(physical,emotional,role,cognitive &social),3 symptom scales,GHS/QoL & 6 single items.PF scale=5 questions about participants PF & daily activities(strenuous activities,long walks,short walks,bed/chair rest & needing help with eating,dressing,washing themselves/using the toilet).PF scale scored on 4-point scale(1=Not at All-4=Very Much).GHS/QoL scored on 7-point scale(1=Very Poor- 7=Excellent).Scores were linearly transformed to a range of 0-100,higher scores=higher response level & better QoL.TTCD for PF & GHS/QoL=time from the date of randomization until first confirmed clinically meaningful deterioration,which is decrease from baseline in PF/GHS score that must be held for at least 2 consecutive assessments/initial decrease above baseline followed by death attributable to cancer progression within 6 weeks of the last deteriorated assessment.Score change≥10-point change in subscale score,considered meaningful.

FAS included all participants randomized into the randomized phase, regardless of whether or not the assigned study treatment was received.