The hydrochloride salt form of parsaclisib, an inhibitor of the delta isoform of phosphoinositide-3 kinase (PI3K) with potential antineoplastic activity. Parsaclisib inhibits the delta isoform of PI3K and prevents the activation of the PI3K/AKT signaling pathway. This both decreases proliferation and induces cell death in PI3K-delta-overexpressing tumor cells. Unlike other isoforms of PI3K, PI3K-delta is expressed primarily in hematopoietic disease and cell lineages. The targeted inhibition of PI3K-delta is designed to preserve PI3K signaling in normal, non-neoplastic cells. PI3K, an enzyme often overexpressed in cancer cells, plays a crucial role in tumor cell regulation and survival.