Polatuzumab Vedotin
Droga
Polatuzumab vedotin IV infusion will be administered as per the schedule specified in the respective arm.
Rituximab IV infusion will be administered as per the schedule specified in the respective arm.
Cyclophosphamide IV infusion will be administered as per the schedule specified in the respective arm.
Doxorubicin IV infusion will be administered as per the schedule specified in the respective arm.
Vincristine IV infusion will be administered as per the schedule specified in the respective arm.
Vincristine Placebo
Droga
Placebo matching to vincristine will be administered as per the schedule specified in the respective arm.
Prednisone PO will be administered as per the schedule specified in the respective arm.
Polatuzumab vedotin Placebo
Droga
Placebo matching to polatuzumab vedotin will be administered as per the schedule specified in the respective arm.