Ibrutinib in patients with relapsed/refractory mantle cell lymphoma: a real-life, retrospective, multicenter trial on behalf of the "RTL" (regional Tuscan lymphoma network).

Background: Relapsed or refractory (R/R) mantle-cell lymphoma (MCL) patients have a poor prognosis and their management is challenging, in absence of a golden standard as salvage treatment. Bruton's tyrosine kinase inhibitor ibrutinib represents an effective treatment for R/R MCL patients. We investigated ibrutinib efficacy and safety in daily clinical practice, together with factors that could predict disease outcome.

Patients and methods: We retrospectively analyzed 69 consecutive R/R MCL patients managed in 10 Tuscan onco-hematological centers. The treatment regimen consisted of oral, continuous, single-agent ibrutinib, maximum dosage of 560 mg once per day, until disease progression.

Results: Overall response rate was 62.3%, with a CR rate of 39.1%. After a median follow-up of 15.6 months, 40/69 patients (58%) were alive, the main cause of death was progressive disease (PD, 22/69 cases, 31.9%). Median progression-free survival (PFS) and overall survival (OS) were 17 and 34.8 months. Inferior PFS was associated with >1 prior line of therapy and B symptoms. Ibrutinib refractoriness was associated with inferior OS, median OS after ibrutinib failure was only 5 months.

Discussion and conclusion: In this real-life setting ibrutinib treatment prolonged survival in R/R MCL patients, without unexpected adverse events. Patients receiving ibrutinib as 2^nd line regimen had the most favorable outcome.