GDC-0941

A potent, selective, orally bioavailable inhibitor of class I PI3Ks with IC50 of 3/33/3/75 nM for p110α/β/γ/δ, respectively; shows similar activity for mutant p110α E545K and H1047R (IC50=3 nM), weak or little activity for C2α, Vps34, DNA-PK, and mTOR (IC50>500 nM) ; inhibits Akt (Ser473) phosphorylation in U87MG, PC3, and MDA-MB-361 cells with IC50s of 46, 37, and 28 nM, respectively, and respective GI50 is 0.95, 0.28, and 0.72 uM; exhibits tumor growth inhibition in U87MG human glioblastoma xenografts.Breast Cancer Phase 2 Clinical (In Vitro) :Pictilisib (GDC-0941) and RP-56976 reduce tumor cell viability by 80% or greater in the breast cancer cell lines than single-agent treatment. GDC-0941 inhibits Akt phosphorylation and downstream targets of Akt signaling such as pPRAS40 and pS6 in Hs578T1.2 (PI3Kα wild-type), MCF7-neo/HER2 (PI3Kα-mutant), and MX-1 (PTEN-null) tumor models. Pictilisib (GDC-0941) decreases the time of RP-56976-induced mitotic arrest prior to apoptosis. Pictilisib (GDC-0941) shows a high efficacy of antitumor activity in two ZD1839-resistant non-small cell lung cancer (NSCLC) cell lines, A549 and H460. Pictilisib (GDC-0941) is highly efficacious in combination with U0126 in inducing cell growth inhibition, G0-G1 arrest and cell apoptosis. H460 cells with activating mutations of PIK3CA are relatively more sensitive to Pictilisib (GDC-0941) than A549 cells with wild-type PIK3CA. Pictilisib (GDC-0941) reduces PI3K pathway activity in both cell lines, illustrated by decreased pAK. Pictilisib (GDC-0941) significantly reduces secreted VEGF detected in the medium after hypoxic/anoxic exposure in all cells. (In Vivo) :Pictilisib (GDC-0941) (150 mg/kg, p.o.) leads to tumor stasis in MCF7-neo/HER2-bearing animals model. Pictilisib (GDC-0941) and RP-56976 result in tumor regressions during the treatment period leading to enhanced antitumor responses. Tumours in the Pictilisib (GDC-0941) -treated mice show a marked non-linear shrinkage, and when the Pictilisib (GDC-0941) treatment ceased, the tumours in the test cohort mice grow again. Pictilisib (GDC-0941) (25 or 50 mg/kg) reduces tumor growth and PI3K and HIF-1 pathway activity in eGFP-FTC133 tumor-bearing mice.