Chronic lymphocytic leukemia (CLL) is a type of cancer characterized by the abnormal formation of lymphocytes by the bone marrow. Obinutuzumab, in combination with venetoclax, is used as a fixed-duration treatment for CLL, but some studies suggest that chlorambucil-obinutuzumab combination therapy could be more effective. This study aims to compare the efficacy of venetoclax-obinutuzumab and chlorambucil-obinutuzumab in patients with previously untreated CLL.

This multicenter, open-label, randomized, phase3 trial included a total of 432 patients aged 18 years or older with untreated CLL. The patients were randomly assigned in a 1:1 ratio to receive venetoclax-obinutuzumab (n=216) or chlorambucil-obinutuzumab (n=216). The primary outcome of the study was investigator-assessed progression-free survival.

At a median follow-up of 39.6 months, patients given venetoclax-obinutuzumab had a significantly longer progression-free survival compared with those who received chlorambucil-obinutuzumab. The median progression-free survival was not attained in the venetoclax-obinutuzumab, as compared with 35.6 months in the chlorambucil-obinutuzumab group. Neutropenia was the only commonly occurring grade 3 or 4 serious adverse events in the two groups.

The research concluded that venetoclax-obinutuzumab combination therapy resulted in a significantly longer progression-free survival, as compared with chlorambucil-obinutuzumab combination therapy in patients with previously untreated CLL.