An Open-label, Multi-center, Three Arm Randomized Study to Investigate the Safety and Efficacy on Progression-free Survival of RO5072759 + Chlorambucil (GClb) Compared to Rituximab + Chlorambucil (RClb) or Chlorambucil (Clb) Alone in Previously Untreated CLL Patients With Comorbidities.

This open-label, randomized, 3-arm study will evaluate the efficacy and safety of obinutuzumab (RO5072759) in combination with chlorambucil as compared to rituximab plus chlorambucil or chlorambucil alone in patients with previously untreated chronic lymphocytic leukemia (CLL). Patients will be randomized 2:2:1 to receive a maximum of six 28-day cycles of either RO5072759 (1000 mg intravenous (iv) infusion, on days 1, 8 and 15 of cycle 1 and day 1 of cycles 2-6) plus chlorambucil (0.5 mg/kg orally, days 1 and 15 of cycles 1-6), or rituximab (iv infusion day 1, 375 mg/m\^2 cycle 1, 500 mg/m\^2 cycles 2-6) plus chlorambucil, or chlorambucil alone. Anticipated time on study treatment is \>6 months and follow-up for disease-progression and safety will be at least 5 years. In the US, this trial is sponsored/managed by Genentech.