157 Background: Multiple signaling pathways are involved in the development of CRPC. We previously showed that the mTOR pathway is activated in CRPC cell lines while inhibition of this pathway results in upregulation of androgen receptor (AR) signaling (Wang et al, Oncogene. 2008). Simultaneous blockade of the mTOR and AR pathways synergize in inducing PCa cell death and delaying tumor formation in mouse models. We hypothesize that simultaneous blockade of the AR and mTOR pathways in CRPC patients with bicalutamide and everolimus will result in improved efficacy compared to bicalutamide alone. Methods: A phase II clinical trial with a lead-in safety phase was designed to determine the efficacy and tolerability of the bicalutamide and everolimus combination in CRPC patients compared with bicalutamide alone. Patients must have histologically confirmed disease and demonstrated disease progression (either by PSA or radiographically) while on androgen deprivation therapy. At the lead-in phase, all patients receive both agents. At the phase II stage, patients are randomized to bicalutamide +/− everolimus. The primary endpoint is PSA response. The second endpoints include progression-free survival, time-to-treatment failure, overall survival and toxicity. Here, we report the results of the lead-in phase. Results: Eight patients were recruited at the lead-in phase. The bicalutamide/everolimus combination was well tolerated with no unexpected toxicities. Six of 8 patients have had PSA response after at least 8 weeks of therapy and the remaining two patients had stable PSA response. The median time to disease progression was 6.8 months. Nine patients have been recruited at the phase II stage so far. This clinical trial is being subcontracting to the other sites of the California Cancer Consortium. Tumor and blood specimens are being collected for molecular correlative studies of mTOR pathway markers. Conclusions: The rational combination of bicalutamide and everolimus appears to have promising anti-tumor activity and an acceptable toxicity profile. The randomized phase of the clinical trial is currently ongoing and will be reported. Supported by Novartis. [Table: see text]
Phase II Clinical Trial of Everolimus in a Pan-Cancer Cohort of Patients with mTOR Pathway Alterations