NCIt definition : An orally bioavailable inhibitor of the class I phosphatidylinositol 3-kinase (PI3K)
beta isoform with potential antineoplastic activity. PI3K beta inhibitor SAR260301
selectively inhibits PI3K beta kinase activity in the PI3K/Akt/mTOR pathway, which
may result in apoptosis and growth inhibition in PI3K beta-expressing and/or phosphatase
and tensin homolog (PTEN)-deficient tumor cells. Dysregulation of the PI3K/Akt/mTOR
pathway is frequently found in solid tumors and contributes to increased tumor cell
growth, tumor cell survival, and resistance to both chemotherapy and radiotherapy.
PI3K beta is the p110-beta catalytic subunit of the class I PI3K. PTEN, a tumor suppressor
protein and negative regulator of PI3K activity, is often mutated in a variety of
cancer cells. By specifically targeting class I PI3K beta, this agent may be more
efficacious and less toxic than pan-PI3K inhibitors.;