Bruton Tyrosine Kinase Inhibitors in Mantle Cell Lymphoma: What Are the Current Options?

Mantle Cell Lymphoma (MCL) is an aggressive B-cell non-Hodgkin lymphoma characterized by the hallmark t(11;14)(q13;q32) translocation, resulting in cyclin D1 overexpression. Predominantly affecting elderly males, MCL exhibits marked clinical and biological heterogeneity, ranging from indolent SOX11-negative variants to highly proliferative blastoid variants. Despite initial responsiveness to chemoimmunotherapy, relapse is frequent, and median overall survival remains limited. Aberrant B-cell receptor (BCR) signaling—mediated by kinases including Bruton's tyrosine kinase (BTK)—plays a central role in MCL pathogenesis. BTK inhibitors (BTKis) such as ibrutinib (as monotherapy or combined with R-CHOP/R-DHAP), acalabrutinib (with rituximab and bendamustine), and pirtobrutinib have significantly improved outcomes of relapsed/refractory disease. However, their efficacy is challenged by resistance mutations (e.g., BTK C481S) and off-target toxicities. Next-generation reversible BTKis represent an important advance, offering activity in the setting of resistance and improved tolerability. Resistance is further sustained by the tumor microenvironment through stromal support and immunosuppressive cellular interactions. Consequently, combination strategies incorporating BTKis with BCL-2 inhibitors, monoclonal antibodies, and cellular therapies are being investigated to enhance response depth and durability. In parallel, biomarker-driven approaches and precision-medicine strategies are emerging to personalize disease monitoring and treatment selection. Collectively, these developments underscore the evolving role of BTK inhibition within broader immune-based and targeted treatment paradigms in MCL.