ORR was defined as the percentage of participants with partial response (PR) or complete response (CR) as defined by Response Evaluation Criteria in Solid Tumors (RECIST) 1.1. Criteria for CR: Disappearance of all target lesions; all lymph nodes must be of non-pathological in size (less than [<]10 millimeter [mm] short axis; normalization of tumor marker level. Criteria for PR: greater than or equal to (>=)30 percent (%) decrease in sum of the diameter of all target lesions compared with baseline, in absence of new lesions or unequivocal progression of non-target lesions. Overall Response (OR) = CR + PR. The outcome measure (OM) was planned to be reported for participants based on their initial assignment to Randomized Phase: Atezolizumab'.

Intent-to-treat (ITT) analysis set included all participants who had entered the Randomized phase of the study.

An adverse event (AE) is any untoward medical event that occurs in a participant administered an investigational product, and it does not necessarily indicate only events with clear causal relationship with the relevant investigational product. Crossover participants were counted twice (in 'Randomized Phase: Atezo arm' and in 'Randomized Phase: Atezo Crossed Over to Dara + Atezo') for safety analysis. For cross-over participants, AEs after initiation of cross-over treatment were summarized separately in the crossover arm, however, AEs occurred before crossover treatment were included in 'Randomized Phase: Atezolizumab arm'.

Safety analysis set included all participants who had received at least 1 administration of any study medication.

Duration of response was defined as duration from date of initial documentation of disease response to date of first objectively documented evidence of recurrence or progressive disease (PD) or death, whichever occurred first. PD: Sum of diameters increased by >=20% and >=5 millimeter (mm) from nadir (including baseline if it was smallest sum). Participants with measurable disease: for "unequivocal progression" based on non-target disease, overall level of substantial worsening that merits discontinuation of therapy (if target disease was stable disease [SD]/PR). Participants without measurable disease: for "unequivocal progression" of non-target disease, increase in overall tumor burden comparable to increase required for PD of measurable disease. Appearance of 1/ more new lesions or unequivocal progression of non-target lesion was also considered as PD. The OM was planned to be reported for participants based on their initial assignment to 'Randomized Phase: Atezolizumab'.

ITT analysis set included all participants who had entered the Randomized phase of the study. Here, N (number of participants analyzed) signifies number of participants who were evaluable for this outcome measure.

Clinical benefit rate was defined as percentage of participants who achieved disease control (CR, PR, or SD). RECIST 1.1 Criteria for CR: Disappearance of all target lesions; all lymph nodes of non-pathological in size (<10 mm short axis); normalization of tumor marker level. Criteria for PR: >=30 % decrease in sum of the diameter of all target lesions compared with baseline, in absence of new lesions or unequivocal progression of non-target lesions. Criteria for SD: <30% decrease in sum of diameters of all target lesions compared with baseline and <20% increase compared with nadir, in absence of new lesions or unequivocal progression of nontarget lesions. The OM was planned to be reported for participants based on their initial assignment to 'Randomized Phase: Atezolizumab'.

ITT analysis set included all participants who had entered the Randomized phase of the study.

PFS was defined as the duration from the date of randomization until the first documented disease progression (PD) or death, whichever occurred first. PD: Sum of diameters increased by >=20% and >=5 millimeter (mm) from nadir (including baseline if it was smallest sum). Participants with measurable disease: for "unequivocal progression" based on non-target disease, overall level of substantial worsening that merits discontinuation of therapy (if target disease was stable disease [SD]/PR). Participants without measurable disease: for "unequivocal progression" of non-target disease, increase in overall tumor burden comparable to increase required for PD of measurable disease. Appearance of 1/ more new lesions or unequivocal progression of non-target lesion was also considered as PD. The OM was planned to be reported for participants based on their initial assignment to 'Randomized Phase: Atezolizumab'.

ITT analysis set included all participants who had entered the Randomized phase of the study.

Overall Survival was defined as the duration from the date of randomization to the date of participant's death due to any cause. The OM was planned to be reported for participants based on their initial assignment to 'Randomized Phase: Atezolizumab'.

ITT analysis set included all participants who had entered the Randomized phase of the study.

Daratumumab serum concentrations were reported. Each cycle was of 21-days. The OM was planned to be reported for participants based on their initial assignment to 'Randomized Phase: Atezolizumab'.

Pharmacokinetic (PK)-evaluable analysis set included all participants who had received at least 1 dose of daratumumab or atezolizumab and had at least 1 postinfusion sample collected. Here 'n' (number of participants analyzed) signifies those participants who were evaluable for this outcome measure at a given time point.

Atezolizumab serum concentrations were reported. Each cycle was of 21-days. The OM was planned to be reported for participants based on their initial assignment to 'Randomized Phase: Atezolizumab'.

PK-evaluable analysis set: all participants who received at least 1 dose of daratumumab/atezolizumab and had at least 1 postinfusion sample collected. Here N (number of participants analyzed): participants evaluable for this outcome measure, and n (number of participants analyzed): participants evaluable for this outcome measure at given timepoint.

Number of participants with antibodies to daratumumab (tested using a validated immunoassay method) were reported. The OM was planned to be reported for participants based on their initial assignment to 'Randomized Phase: Atezolizumab'.

The immunogenicity-evaluable analysis set included all participants who received at least 1 dose of atezolizumab or daratumumab and had appropriate samples for detection of antibodies to atezolizumab or daratumumab. Here 'N' (number of participants analyzed) signifies those participants who were evaluable for this outcome measure.

Number of participants with antibodies to atezolizumab (tested using a validated immunoassay method) were reported. The OM was planned to be reported for participants based on their initial assignment to 'Randomized Phase: Atezolizumab'.

The immunogenicity-evaluable analysis set included all participants who received at least 1 dose of atezolizumab or daratumumab and had appropriate samples for detection of antibodies to atezolizumab or daratumumab.