This is a phase III, randomized, partially blinded, multicenter trial to evaluate the efficacy and safety of atezolizumab plus bevacizumab and chemotherapy compared to placebo plus bevacizumab and chemotherapy in patients with recurrent ovarian-, fallopian tube, or primary peritoneal cancer with 1st or 2nd relapse within 6 months after platinum based chemotherapy or 3rd relapse.

Approximately 550 patients will be randomized in a 1:1 ratio to the treatments as specified below: Arm A: Chemotherapy + Bevacizumab + Placebo Arm B: Chemotherapy + Bevacizumab + Atezolizumab Study treatment will continue until disease progression per RECIST v1.1, unacceptable toxicity, or patient or investigator decision to discontinue treatment. Atezolizumab/placebo, chemotherapy and bevacizumab may be discontinued for toxicity independently of each other in the absence of disease progression. For each patient, chemotherapy (PLD or Paclitaxel weekly) will be selected by the investigator prior to randomization. Recruitment to an individual chemotherapy cohort will be closed once 50% of patients are recruited to this cohort. In such case the remaining cohort will remain open for recruitment.