Carfilzomib, Lenalidomide, Dexamethasone (KRD) in BTKi relapsed or refractory mantle cell lymphoma: a phase II study from Fondazione Italiana Linfomi

Mantle cell lymphoma (MCL) is a rare lymphoproliferative neoplasm considered incurable, with a median survival of 3–5 years. In recent years, Bruton's tyrosine kinase inhibitors (BTKi) have been introduced, demonstrating high therapeutic activity. However, the prognosis for MCL patients failing ibrutinib therapy is particularly poor, with a survival expectation of a few months. In this phase II trial, we assessed the efficacy and safety of the carfilzomib-lenalidomide-dexamethasone (KRD) combination in MCL patients who were relapsed/refractory (R/R) or intolerant to BTKi and in need of treatment. The primary objective of the study was to evaluate the antitumor efficacy of the KRD combination in terms of 12-month overall survival (12-month OS). From September 2019 to December 2020, 16 patients were enrolled from 11 Italian centers. After a median follow-up of 2.37 months (95% CI 0.92–6.47), the 12-month OS was 13%. The rate of grade 3–4 adverse events (AEs) was 35%, and the overall response rate (ORR) was 19%. These results led to the premature termination of enrollment, as defined in the protocol stopping rules. The efficacy of the KRD combination in advanced-stage MCL patients who are R/R to BTKi is unsatisfactory and too toxic.