CNS relapse in patients with DLBCL treated with lenalidomide plus R-CHOP (R2CHOP): analysis from two phase 2 studies

Central nervous system (CNS) relapse of diffuse large B-cell lymphoma (DLBCL) is a devastating event occurring in ~ 5% of patients treated with R-CHOP. We hypothesized that adding lenalidomide to R-CHOP (R2CHOP) may decrease the risk of CNS relapse. We analyzed records for patients with DLBCL from two R2CHOP trials. We assessed variables pertinent to the CNS-International Prognostic Index (CNS-IPI) scoring system and classified patients into groups of low, intermediate, and high risk of CNS relapse. The 2-year CNS relapse rate for each risk group was estimated using the Kaplan-Meier method and compared with reported rates in cohorts treated with contemporary chemoimmunotherapy. A total of 136 patients were included. Mean age was 65 and median follow-up was 48.2 months. 10.3, 71.3, and 18.4% of patients were classified into low, intermediate, and high-risk CNS-IPI groups, respectively. Only one of 136 patients developed CNS relapse, corresponding to an incidence of 0.7% and an estimated 2-year CNS relapse rate of 0.9% for the entire R2CHOP cohort. The estimated 2-year CNS relapse rates for the low, intermediate, and high-risk groups were 0, 0, and 5.0%, respectively. Frontline therapy with R2CHOP in patients with DLBCL is associated with a lower-than-expected rate of CNS relapse.