N Engl J Med 2018 Mar;378(12):1107-1120
From the Peter MacCallum Cancer Centre, Royal Melbourne Hospital, and University of Melbourne, Melbourne, VIC (J.F.S.), and the John Curtin School of Medical Research, Australian National University, Canberra, ACT (J.D.) - all in Australia; the University of California School of Medicine, San Diego (T.J.K.), and Genentech, South San Francisco (E.A.P., Y.L., M. Mobasher) - both in California; University Hospital Cologne and the Center for Integrated Oncology Cologne-Bonn, Cologne, Germany (B.E.); St. James's University Hospital, Leeds (P.H.), and F. Hoffmann-La Roche, Welwyn Garden City (M.B., K.H.) - both in the United Kingdom; Segal Cancer Center, Lady Davis Institute, Jewish General Hospital, Montreal (S.A.), and the Departments of Medicine and Oncology, University of Calgary, Calgary, AB (C.O.) - all in Canada; Memorial Sloan Kettering Cancer Center, New York (J.G.); the Department of Hematology, Medical University of Lodz and Copernicus Memorial Hospital, Lodz, Poland (T.R.); Hospital Universitario 12 de Octubre, Madrid (J.D.S.); Medical University of Vienna, Department of Medicine I, Division of Hematology and Hemostaseology, Vienna (U.J.); the Department of Hematology, Centre Hospitalier Universitaire Montpellier, Montpellier, France (G.C.); the Department of Onco-Hematology, Division of Hematology, Niguarda Cancer Center, Niguarda Hospital, Milan (M. Montillo); AbbVie, North Chicago, IL (R.H.); and the Department of Hematology, Cancer Center Amsterdam, Academic Medical Center, Amsterdam (A.P.K.).
Background: Venetoclax inhibits BCL2, an antiapoptotic protein that is pathologically overexpressed and that is central to the survival of chronic lymphocytic leukemia cells. We evaluated the efficacy of venetoclax in combination with rituximab in patients with relapsed or refractory chronic lymphocytic leukemia.
Methods: In this randomized, open-label, phase 3 trial, we randomly assigned 389 patients to receive venetoclax for up to 2 years (from day 1 of cycle 1) plus rituximab for the first 6 months (venetoclax-rituximab group) or bendamustine plus rituximab for 6 months (bendamustine-rituximab group). The trial design did not include crossover to venetoclax plus rituximab for patients in the bendamustine-rituximab group in whom progression occurred. The primary end point was investigator-assessed progression-free survival.
Results: After a median follow-up period of 23.8 months, the rate of investigator-assessed progression-free survival was significantly higher in the venetoclax-rituximab group (32 events of progression or death in 194 patients) than in the bendamustine-rituximab group (114 events in 195 patients); the 2-year rates of progression-free survival were 84.9% and 36.3%, respectively (hazard ratio for progression or death, 0.17; 95% confidence interval [CI], 0.11 to 0.25; P<0.001 by the stratified log-rank test). The benefit was maintained across all clinical and biologic subgroups, including the subgroup of patients with chromosome 17p deletion; the 2-year rate of progression-free survival among patients with chromosome 17p deletion was 81.5% in the venetoclax-rituximab group versus 27.8% in the bendamustine-rituximab group (hazard ratio, 0.13; 95% CI, 0.05 to 0.29), and the 2-year rate among those without chromosome 17p deletion was 85.9% versus 41.0% (hazard ratio, 0.19; 95% CI, 0.12 to 0.32). The benefit of venetoclax plus rituximab over bendamustine plus rituximab was confirmed by an independent review committee assessment of progression-free survival and other secondary efficacy end points. The rate of grade 3 or 4 neutropenia was higher in the venetoclax-rituximab group than in the bendamustine-rituximab group, but the rates of grade 3 or 4 febrile neutropenia and infections or infestations were lower with venetoclax than with bendamustine. The rate of grade 3 or 4 tumor lysis syndrome in the venetoclax-rituximab group was 3.1% (6 of 194 patients).
Conclusions: Among patients with relapsed or refractory chronic lymphocytic leukemia, venetoclax plus rituximab resulted in significantly higher rates of progression-free survival than bendamustine plus rituximab. (Funded by Genentech and AbbVie; ClinicalTrials.gov number, NCT02005471 .).