A Prospective, Open-Label, Multicenter, Phase 2 Trial to Evaluate the Safety and Efficacy of the Combination of Tirabrutinib (ONO/GS-4059) and Idelalisib with and without Obinutuzumab in Patients with Relapsed/Refractory Chronic Lymphocytic Leukemia (CLL)

Introduction: Several targeted therapies have been added to the treatment landscape of CLL. These agents have more favorable toxicity profiles compared with chemotherapy, but achieve only low complete remission (CR) rates. However, combination regimens with targeted drugs have the potential for improved duration and depth of response while exhibiting an acceptable safety profile. Tirabrutinib is a selective, irreversible, second generation, small-molecule BTK inhibitor. Tirabrutinib and idelalisib individually have shown promising results as single-agent therapy in patients (pts) with CLL. This study evaluated tirabrutinib and idelalisib together as dual therapy (TI), and as triple therapy adding obinutuzumab (TIO).