Purity >98% by HPLC. Acalabrutinib (ACP-196) is an orally available, selective irreversible inhibitor of Bruton's tyrosine kinase (BTK) with potential antineoplastic activity. It is a second generation BTK inhibitor with improved pharmacological properties with better plasma exposure, oral absorption and shorter half-life. It prevents the activation of B-cell antigen receptor (BCR) signaling pathway, thus preventing B-cell activation and BTK mediated activation of downstream survival pathways.