GDC-0084 is a potent and brain penetrant inhibitor of PI3K and mTOR with Ki values of 2 nM and 70 nM for PI3Kα and mTOR, respectively [1].

 Glioblastoma (GBM) is the most common primary brain tumor in adults and aberrant PI3K signaling is associated with more than 80% of cases. The PI3K pathway represents a potential target for the treatment of this disease and the inhibitors would need to freely cross the blood-brain barrier (BBB) [1][2].

GDC-0084 is a potent and brain penetrant inhibitor of PI3K and mTOR. In vitro kinase assay, GDC-0084 exhibited Ki values of 2 nM, 46 nM, 3 nM, 10 nM and 70 nM for PI3Kα, PI3Kβ, PI3Kδ, PI3Kγ and mTOR, respectively. In five different GBM cell lines, GDC-0084 had antiproliferative activities with EC50 values ranging from 0.3 to 1.1 μM. GDC-0084 has excellent human metabolic stability in microsomal and hepatocyte incubations [1]. In transfected cell lines over-expressing human or mouse P-gp or BCRP, GDC-0084 was a poor substrate of these efflux transporters. In mice brain, GDC-0084 significantly lowered pAkt and pS6 levels [2].

In rats after a 15 mg/kg dose of GDC-0084, the total brain-to-plasma ratio was 1.9-3.3. In subcutaneous U87 glioblastoma tumor xenograft mice model, GDC-0084 significantly inhibited tumor growth in a dose-dependent way. GDC-0084 also concentration-dependently inhibited pAKT [1].

References:

[1]. Heffron TP1, Ndubaku CO1, Salphati L1, et al. Discovery of Clinical Development Candidate GDC-0084, a Brain Penetrant Inhibitor of PI3K and mTOR. ACS Med Chem Lett. 2016 Feb 16;7(4):351-6.

[2]. Salphati L, Alicke B, Heffron TP, et al. Brain Distribution and Efficacy of the Brain Penetrant PI3K Inhibitor GDC-0084 in Orthotopic Mouse Models of Human Glioblastoma. Drug Metab Dispos. 2016 Dec;44(12):1881-1889. Epub 2016 Sep 16.