PKI-402

PKI-402 is a selective, reversible, ATP-competitive inhibitor of PI3K, including PI3K-α mutants, and mTOR (IC₅₀=2, 3, 7,14 and 16 nM for PI3Kα, mTOR, PI3Kβ, PI3Kδ and PI3Kγ). IC50 & Target: IC50: 2 nM (PI3Kα), 3 nM (mTOR), 7 nM (PI3Kβ),14 nM (PI3Kδ), 16 nM (PI3Kγ)^[1] In Vitro: PKI-402 is an equipotent inhibitor of class I PI3K, including the E545K and H1047R PI3K-α mutants (IC₅₀=2, 3 and 3 nM for PI3Kα, PI3Kα-H1047R and PI3Kα-E545K, respectively). PKI-402 causes in vitro growth inhibition of human tumor cell lines derived from a diverse set of human tumor tissues, including breast, brain (glioma), pancreas, and non-small cell lung cancer (NSCLC) tissues. PKI-402 inhibits MDA-MB-361 [breast: Her2⁺ and PIK3CA mutant (E545K)], with an IC₅₀ of 6 nM. PKI-402 inhibits HCT116 (K-Ras and PIK3CA mutant) with an IC₅₀ of 33 nM^[1]. In Vivo: PKI-402 displays antitumor activity (i.v. route) in breast [MDA-MB-361: Her2⁺ and PIK3CA (E545K)], glioma (U87MG and PTEN), and NSCLC (A549; K-Ras and STK11) xenograft models. PKI-402 causes regression in the MDA-MB-361 xenograft model. PKI-402 effect is most pronounced at 100 mg/kg (daily for 5 days, one round), which reduces initial tumor volume and prevents tumor re-growth for 70 days. In MDA-MB-361 tumor tissue, PKI-402 at 100 mg/kg (single dose) fully suppresses p-Akt at both the T308 and the S473 sites at 8 hours and induces cleaved PARP. At 24 hours, p-Akt suppression is still evident, as is cleaved PARP^[1].