Obinutuzumab (GA101) plus chlorambucil (Clb) or rituximab (R) plus Clb versus Clb alone in patients with chronic lymphocytic leukemia (CLL) and preexisting medical conditions (comorbidities) Final stage 1 results of the CLL11 (BO21004) phase III trial

SUMMARY: Obinutuzumab or GAZYVA® (GA101) is glycoengineered, fully humanized, third generation, type II anti-CD20 antibody (IgG1 monoclonal antibody) that selectivity binds to the extracellular domain of the CD20 antigen on malignant human B cells. It has enhanced antibody-dependent cellular cytotoxicity (ADCC) and strong apoptosis-inducing activity. In contrast, RITUXAN® (Rituximab) is a first generation chimeric anti-CD20 targeted monoclonal antibody. In this phase III trial, LEUKERAN® (Chlorambucil – Clb)) was compared with a combination of GAZYVA® plus LEUKERAN® (GClb) and a combination of RITUXAN® plus LEUKERAN® (RClb). Five Hundred and eighty nine (589) treatment naïve CLL patients over 70 years of age with comorbidities were enrolled of whom 118 patients received Clb, 238 received GClb and 233 received RClb. The primary endpoint was Progression-Free Survival (PFS). Chemoimmunotherapy with both GClb and RClb significantly prolonged PFS compared to Clb alone. The median PFS was 10.8 months with Clb alone compared to 23 months for GClb (HR=0.14, P<0.0001) and 15.7 months for RClb (HR=0.32, P<0.0001). There were no Complete Responses (CR) with Clb alone whereas the CR rates with GClb and RClb were 22% and 8% respectively. This study gives new life to LEUKERAN® when given in combination with CD20 targeted monoclonal antibodies and may be of value when treating elderly patients with comorbid conditions. Goede V, Fischer K, Humphrey K, et al. J Clin Oncol 31, 2013 (suppl; abstr 7004)