Survival of mantle cell lymphoma in the era of Bruton tyrosine kinase inhibitors: a population-based analysis

Front-line and second-line treatment for mantle cell lymphoma in clinical practice: A multicenter retrospective analysis

BACKGROUND

There are few reports of clinical practice treatment patterns and efficacy in mantle cell lymphoma (MCL).

MATERIALS AND METHODS

We retrospectively studied a large, multicenter, cohort of patients with MCL diagnosed between 2000 and 2020 in eight institutions.

RESULTS

536 patients were registered (73% male, median of 70 years). Front-line treatment was based on high-dose cytarabine, bendamustine, and anthracyclines in 42%, 12%, and 15%, respectively. The median PFS for all patients was 45 months; 68, 34, and 30 months for those who received high-dose cytarabine-based, bendamustine-based and anthracycline-based therapy. 204 patients received second-line. Bendamustine-based treatment was the most common second-line regimen (36% of patients). The median second-line PFS (sPFS) for the entire cohort was 14 months; 19, 24, and 31 for bendamustine-, platinum-, and high-dose cytarabine-based regimens, with broad confidence intervals for these latter estimates. Patients treated with cytarabine-based therapies in the front-line and those with front-line PFS longer than 24 months had a substantially superior sPFS.

CONCLUSION

Front-line treatment in this cohort of MCL was as expected and with a median PFS of over 3.5 years. Second-line treatment strategies were heterogeneous and the median second-line PFS was little over 1 year.

Pirtobrutinib: A novel non-covalent BTK inhibitor for the treatment of adults with relapsed/refractory mantle cell lymphoma

OBJECTIVE

To provide a comprehensive review of the pharmacokinetics, pharmacodynamics, safety, and efficacy of a new Food and Drug Administration (FDA) approved Bruton's tyrosine kinase inhibitor (BTKi), pirtobrutinib for relapsed/refractory mantle cell lymphoma (r/r MCL).

DATA SOURCES

A literature search was conducted through PubMed MEDLINE, ClinicalTrials.gov, and the FDA website (January 2018-January 2023) using the following key terms: lymphoma, non-covalent, Bruton's tyrosine kinase (BTK), and relapse. Relevant English language monographs, studies, and abstracts conducted in humans were reviewed and considered.

DATA SUMMARY

Pirtobrutinib, a novel non-covalent BTKi, was granted accelerated approval for treatment of r/r MCL on January 27th, 2023, based on an open-label, multi-center phase 1/2 BRUIN trial. In phase l, 61 patients with r/r MCL received seven dose levels of pirtobrutinib (25-300 mg). There was no reported maximum tolerated dose or dose-limiting toxicities during this study period. In phase 2, 56 r/r MCL evaluable efficacy patients received pirtobrutinib 200 mg daily. The overall response rate (ORR) was 52% (95% CI 38-65). Additionally, patients who received a previous covalent BTKi, ORR was 52% (95% CI 38-66). Neutropenia was the most common adverse reaction reported as a grade 3 or higher.

CONCLUSION

Pirtobrutinib has demonstrated safety and efficacy in heavily pre-treated adult patients with r/r MCL. Advantages of this drug include its usage in patients whose malignancy is resistant to current BTKi, tolerability, and response rate. Multiple clinical trials are underway to determine the efficacy of pirtobrutinib in other B-cell malignancies.

Tumor Microenvironment and Immunotherapy-Based Approaches in Mantle Cell Lymphoma

Mantle cell lymphoma (MCL) is an aggressive B-cell non-Hodgkin lymphoma (NHL) characterized by the translocation t(11;14) (q13;q32) and a poor response to rituximab–anthracycline-based chemotherapy. High-dose cytarabine-based regimens offer a durable response, but an important number of MCL patients are not eligible for intensive treatment and are ideal candidates for novel targeted therapies (such as BTK, proteasome or BCL2 inhibitors, Immunomodulatory Drugs (IMiDs), bispecific antibodies, or CAR-T cell therapy). On the bench side, several studies aiming to integrate the tumor within its ecosystem highlighted a critical role of the tumor microenvironment (TME) in the expansion and resistance of MCL. This led to important insights into the role of the TME in the management of MCL, including potential targets and biomarkers. Indeed, targeted agents often have a combined mechanism of action on the tumor B cell but also on the tumor microenvironment. The aim of this review is to briefly describe the current knowledge on the biology of the TME in MCL and expose the results of the different therapeutic strategies integrating the TME in this disease.