Australian experience with ibrutinib in patients with relapsed/refractory mantle cell lymphoma: a study from the Lymphoma and Related Diseases Registry.

Bruton's tyrosine kinase inhibitors (BTKi) have an established role in the management of patients with relapsed/refractory mantle cell lymphoma (MCL). However, scant data exist on outcomes of patients ineligible for clinical trials testing these therapies. We describe a contemporary cohort of relapsed/refractory MCL patients from the Australasian Lymphoma and Related Diseases Registry treated with ibrutinib December 2014 until July 2018, to determine the proportion potentially eligible for original trials, reasons for ineligibility and survival outcomes. Of 44 patients, 41% met one or more exclusion criteria from previous phase II/III MCL BTKi studies. Median progression-free and overall survival were 13.7 months (95% CI 6.2-28.1) and 15.6 months (95% CI 10.8-29.6) respectively and were shorter in patients excluded from clinical trials based on ECOG ≥2. Ibrutinib has demonstrable clinical effectiveness in a population enriched for unfit and trial-ineligible patients, and a need for more inclusive enrollment criteria in future BTKi studies is highlighted.