Abstract LB-66: Results of two phase I multicenter trials of AZD5363, an inhibitor of AKT1, 2 and 3: Biomarker and early clinical evaluation in Western and Japanese patients with advanced solid tumors . (2013)

Abstract Background: AZD5363 is an oral, potent, and selective inhibitor of AKT1, 2 and 3, with activity in a wide range of tumor cell lines and xenografts dependent upon PI3K/AKT signaling. Methods: Two phase I studies (NCT01226316 [West], NCT01353781 [Japan]) were initiated to define the toxicity, pharmacokinetic (PK), and pharmacodynamic (PD) profile of AZD5363. Two schedules, continuous bid dosing (7/7) and an intermittent schedule bid dosing 4 days on 3 days off (4/7), were investigated. PD biomarkers of AKT signaling were assessed (using pre- and on-treatment samples) in plasma (pPRAS40, pGSK3β, pAKT, glucose, insulin), plucked hair (pPRAS40) and tumor tissue (pPRAS40, pGSK3β, pAKT). Results: At data cut-off (January 2013), 92 patients had been treated in the dose-escalation phases of both studies. In the Western study, the maximum tolerated dose (MTD) for each schedule was 320 mg bid (7/7) and 480 mg bid intermittent dosing (4/7). In the Japanese study, 320 mg bid (7/7) was not tolerated; the MTD for intermittent dosing (4/7) was 480 mg bid. The most commonly reported adverse events, of note, were hyperglycemia, rash, and diarrhea. The PK profile suggests a dose proportional increase in Cmax and AUC. Exposures achieved at doses of 320 mg bid (7/7) and 480 mg bid (4/7) and above are consistent with activity seen in xenograft models. At the doses described, target engagement was seen as evidenced by PD changes in normal tissue (&amp;gt;50% reduction in pPRAS40 in 7/10 patients on AZD5363 480 mg bid (4/7) in plucked hair samples and 30-50% reduction in pPRAS40 and &amp;gt;30% reduction in pGSK3β in platelet rich plasma). Importantly, 7/9 paired biopsies showed an increase in pAKT consistent with the non allosteric inhibition of AKT. Investigation of another intermittent schedule of AZD5363 bid, 2 days on/5 days off treatment, is ongoing. Exploratory mutation analyses of plasma samples are ongoing. Two partial responses were observed, one endometrioid cancer of the ovary and one cervical cancer, in patients on AZD5363 at 480 mg bid (4/7) and 400 mg bid (7/7), respectively. Mutation of either AKT1 or PIK3CA was identified in tumor tissue from both patients. A further patient, with endometrioid cancer of ovary (PIK3CA mutation), had stable disease (SD) for 156 days. Conclusions: AZD5363 administered at 480 mg bid (4/7) was generally well tolerated and showed a PK and PD profile consistent with activity in preclinical models. Partial responses were noted in patients with mutations driving the PI3K pathway. Footnote: AZD5363 was discovered by AstraZeneca subsequent to collaboration with Astex Therapeutics (and its collaboration with the Institute of Cancer Research and Cancer Research Technology Ltd). Citation Format: Udai Banerji, Malcolm Ranson, Jan HM Schellens, Taito Esaki, Emma Dean, Andrea Zivi, Ruud van der Noll, Paul K. Stockman, Marcelo Marotti, Michelle D. Garrett, Barry R. Davies, Paul Elvin, Andrew Hastie, Peter Lawrence, SY Amy Cheung, Christine Stephens, Kenji Tamura. Results of two phase I multicenter trials of AZD5363, an inhibitor of AKT1, 2 and 3: Biomarker and early clinical evaluation in Western and Japanese patients with advanced solid tumors . [abstract]. In: Proceedings of the 104th Annual Meeting of the American Association for Cancer Research; 2013 Apr 6-10; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2013;73(8 Suppl):Abstract nr LB-66. doi:10.1158/1538-7445.AM2013-LB-66