Genentech announced positive data from a second stage, Phase 3 CLL11 study comparing Gazyva (obinutuzumab) to Rituxan (rituximab), both in combination with chlormabucil for people with previously untreated chronic lymphocytic leukemia (CLL) and co-existing medical conditions. 

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Gazyva is a new monoclonal antibody designed to attach to CD20 and attack targeted cells both directly and together with the body’s immune system.

CLL11 is a multicenter, open-label, randomized three-arm study investigating the efficacy and safety profile of Gazyva plus chlorambucil, Rituxan plus chlorambucil and chlorambucil alone in 781 previously untreated people with CLL and co-existing medical conditions who are in need of therapy. 

Stage 1 (n=589) compared Gazyva plus chlorambucil to chlorambucil alone and Rituxan plus chlorambucil to chlorambucil alone. Stage 2 (n=663) compared Gazyva plus chlorambucil directly with Rituxan plus chlorambucil. The primary endpoint of the study was progression-free survival (PFS).

In the Stage 2 study, patients in the Gazyva arm achieved a median PFS of 26.7 months compared with 15.2 months for those in the Rituxan arm (HR 0.39, CI 0.31-0.49, P<0.0001). 

A comparison of data from the Gazyva and Rituxan treatment arms showed higher complete response rates (21% compared with 7%) and a ten-fold increase in the percentage of people achieving minimal residual disease (MRD) negativity (29.4% compared with 2.5%), defined as no detectable disease in the blood at the end of the treatment course.

An updated analysis from the first stage (Stage 1a) of the CLL11 study showed that people treated with Gazyva in combination with chlorambucil lived longer (overall survival, or OS) compared to chlorambucil alone (HR 0.41, 95% CI 0.23-0.74, P=0.002). Given the median observation time of 23 months, median overall survival has not yet been reached in any of the study arms.

Previously the FDA granted Gazyva Breakthrough Therapy Designation and approved its use in combination with chlorambucil to treat patients with previously untreated chronic lymphocytic leukemia (CLL).

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