Addition of rituximab in relapsed/refractory chronic lymphocytic leukemia after progression on venetoclax monotherapy.

Venetoclax is approved as monotherapy and in combination with rituximab for relapsed/refractory (R/R) chronic lymphocytic leukemia (CLL). Two Phase 1 studies (M12-175 [NCT01328626]; M13-365 [NCT01682616]) were conducted in which patients who initially responded and then progressed on venetoclax monotherapy could receive added rituximab. Ten patients were evaluated (M12-175, n = 8; M13-365, n = 2), and five (50%) responded again upon addition of rituximab, including three complete and two partial responses. Responses were ongoing after 5-10 months of follow-up. Addition of rituximab was well tolerated. These findings indicate potential clinical benefit with rituximab added to venetoclax post-progression in some patients with R/R CLL.