Acalabrutinib is a targeted oral therapy known as a Bruton's tyrosine kinase (BTK) inhibitor, which plays a critical role in blocking B-cell receptor signaling essential for the survival and proliferation of malignant B-cells. It was developed by Acerta Pharma, later part of AstraZeneca, as a more selective alternative to first-generation BTK inhibitors like ibrutinib, with the aim of reducing off-target effects such as bleeding and cardiovascular complications. Preclinical studies demonstrated its potent inhibition of BTK and favorable pharmacokinetics, paving the way for clinical trials. Phase I and II trials established its safety, tolerability, and initial efficacy in patients with relapsed or refractory chronic lymphocytic leukemia (CLL) and mantle cell lymphoma (MCL), while subsequent Phase III trials confirmed its effectiveness, leading to regulatory approval. The U.S. Food and Drug Administration (FDA) first approved acalabrutinib in 2017 for relapsed or refractory MCL, and later approvals expanded its use to CLL and small lymphocytic lymphoma (SLL). As a next-generation BTK inhibitor, acalabrutinib has become a significant advancement in the treatment of B-cell malignancies, offering comparable efficacy to earlier drugs with improved tolerability and safety.
