Zanubrutinib is a novel Bruton’s tyrosine kinase (BTK) inhibitor used for the treatment of adult patients with mantle cell lymphoma (MCL) who have received at least one prior therapy. Mantle cell lymphoma is an aggressive mature B-cell non-Hodgkin lymphoma associated with early relapse, poor clinical outcomes, and long-term survival. BTK is an enzyme that plays a role in oncogenic signalling pathways, promoting the survival and proliferation of malignant B cells. Compared to the first-generation BTK inhibitor [ibrutinib], zanubrutinib displays higher potency and selectivity for BTK with fewer off-target effects. Due to this enhanced selectivity towards BTK, zanubrutinib belongs to the second-generation BTK inhibitor drug group that also includes [acalabrutinib], which was approved by the FDA in 2017. Zanubrutinib was granted accelerated approval by the FDA in November 2019 based on clinical trial results that demonstrated an 84% overall response rate from zanubrutinib therapy in patients with MCL, which measures the proportion of patients in a trial whose tumour is entirely or partially destroyed by a drug. It is currently marketed under the trade name BRUKINSA™ and is available as oral capsules. In August 2021, the FDA granted accelerated approval to zanubrutinib for the treatment of adults with Waldenström’s macroglobulinemia. This indication is valid in the US, Europe, and Canada. In September 2021, zanubrutinib was granted another accelerated approval for the treatment of relapsed or refractory marginal zone lymphoma who have received at least one anti-CD20-based regimen. In October 2022, the EMA’s Committee for Medicinal Products for Human Use (CHMP) recommended zanubrutinib be granted marketing authorization for the treatment of chronic lymphocytic leukemia.