Efficacy of Idelalisib and Rituximab in Relapsed/Refractory Chronic Lymphocytic Leukemia Treated Outside of Clinical Trial. a Report of the Gimema Group

Background.The PI3Kδ inhibitor idelalisib given in combination with rituximab in relapsed/refractory chronic lymphocytic leukemia (R/R CLL) has been associated with an objective response in 81% of cases with a median PFS of 20.3 months in a phase-3 clinical trial (Sharman et al, JCO 2019). Because the efficacy of new drugs reported in clinical trials may not translate into similar results in the day-to-day practice, we performed an observational retrospective-prospective study on the efficacy and safety of idelalisib and rituximab (IR) in R/R CLL patients treated outside of clinical trials in Italian centers belonging to the GIMEMA group.