摘要
Activation of AKT signaling by PTEN loss or PIK3CA mutations occurs frequently in human cancers, but targeting AKT has been difficult due to the mechanism-based toxicities of inhibitors that target the inactive conformation of AKT. Ipatasertib (GDC-0068) is a novel selective ATP-competitive small-molecule inhibitor of AKT that preferentially targets active phosphorylated AKT (pAKT) and is potent in cell lines with evidence of AKT activation. In this phase I study, ipatasertib was well tolerated; most adverse events were gastrointestinal and grade 1-2 in severity. The exposures of ipatasertib >= 200 mg daily in patients correlated with preclinical TGI(90), and pharmacodynamic studies confirmed that multiple targets (i.e., PRAS40, GSK3 beta, and mTOR) were inhibited in paired on-treatment biopsies. Preliminary antitumor activity was observed; 16 of 52 patients (30%), with diverse solid tumors and who progressed on prior therapies, had radiographic stable disease, and many of their tumors had activation of AKT. SIGNIFICANCE: Potent inhibition of AKT signaling with ipatasertib was associated with a tolerable safety profi le and meaningful disease control in a subgroup of patients. Targeting pAKT with an ATP-competitive inhibitor provides a greater therapeutic window than allosteric inhibitors. Further investigation with ipatasertib is ongoing in phase II studies. Cancer Discov; 7( 1); 102-13.
- 出版日期2017-1