Parsaclisib hydrochloride (INCB050465 hydrochloride) is a potent, selective and orally active inhibitor of PI3Kδ, with an IC50 of 1 nM at 1 mM ATP. Parsaclisib hydrochloride shows approximately 20000-fold selectivity over other PI3K class I isoforms. Parsaclisib hydrochloride can be used for the research of relapsed or refractory B-cell malignancies.