Five year experience in ibrutinib therapy for relapsed and refractory mantle cell lymphoma in real world Russian clinical practice

Background. Mantle cell lymphoma (MCL) is a rare and clinically aggressive lymphoma subtype. Current approaches have greatly improved patients outcomes, but relapse is inevitable. In phase IIIII clinical trials, ibrutinib has shown significant activity in patients with relapsed or refractory (R/R) MCL. Aim. To assess efficacy and toxicity of ibrutinib monotherapy in patients with R/R MCL in routine practice outside of clinical trials. Materials and methods. The study enrolled patients with confirmed R/R MCL who had received at least one line of previous chemotherapy. ECOG 24, cytopenia, infectious complications, hemorrhagic syndrome were not exclusion criteria. Patients received daily oral ibrutinib 560 mg until progression or unacceptable toxicity. Results. From May 2015 to September 2020 ibrutinib therapy was started in 106 patients with R/R MCL in 16 regions of Russia. The median age was 66 years; ECOG2 18%, blastoid variant (or Ki6740% or WBC50109/l) 43%. The median number of previous treatment lines was 2 (111). The ORR was 78.4% (CRR 27.4%). The median PFS was 13.6 months and OS 23.2 months. In the blastoid group the median PFS was 4.4 months vs 36.5 months in the alternative group (p0.001), the median OS 9.0 vs 41.0 (p=0.001). The median OS of patients after progression on ibrutinib was 3.2 months. The common complications are hemorrhages (63%), diarrhea (62%), myalgia and muscle cramps (60%), infections (31%), skin and nail toxicity 15%, arrhythmia 8%. None of recipients had to completely discontinue ibrutinib therapy due to complications. Conclusion. Ibrutinib is effective and well tolerated in routine practice of R/R MCL treatment and our results are consistent with international clinical trials. The favorable toxicity profile and the high response rate made it possible to prescribe ibrutinib in severe somatic status, cytopenia, and even in the presence of infectious complications