Low-dose RAD001(Everolimus) Plus Cisplatin-HDFL Chemotherapy for the First-line Treatment of Advanced Gastric Cancer

Non-resectable gastric cancer is an incurable disease, with a median survival of 4 months if untreated. Systemic chemotherapy confers prolongation of survival and improvement of quality of life. Regimens containing cisplatin and 5-fluorouracil (5-FU) are widely adopted in the world. The overall response rate and median overall survival of the P-HDFL regimen (cisplatin and weekly 24-hour infusion of high-dose 5-FU and leucovorin) for advanced gastric cancer are 60% (45%-76%, 95% C.I.) and 10 months, respectively. This regimen (P-HDFL) is very popular in Taiwan because of high objective response rates and low treatment-related toxicities. Adding a third active chemotherapeutic agent to cisplatin and 5-FU doublet does not seem to improve efficacy. Further, most of the patients with recurrent or metastatic gastric cancer are frequently associated with a poor general condition which prohibits intensive chemotherapy. Therefore, combination of P-HDFL with biologic agents(such as everolimus, etc.)is an attractive alternative.

PI3K/Akt/mTOR pathway is actively participating in cell proliferation and survival of human gastric cancers. We have recently demonstrated that RAD001(everolimus),an mTOR inhibitor, although with only modest growth inhibitory effects as a single agent, has significant synergistic cytotoxicity with cisplatin and 5-FU in gastric cancer cells. The concentration of RAD001 needed for synergism with cisplatin and 5-FU is as low as 0.5 to 5 nM. And, as expected, RAD001 has significant inhibition of downstream molecules such as 4E-BP1 and S6Kinase, in human gastric cancer cells. It is therefore reasonable to conduct a phase II study to examine if the combination of a relatively low dose of RAD001 and P-HDFL may improve the outcome of advanced gastric cancer.

This is an open-label, multi-center, phase II trial using low-dose RAD001 (10 mg po on D1,D8,\&D15) plus P-HDFL chemotherapy (cisplatin 35 mg/m2 ivd 24 hrs on D1 \& D8; 5-FU 2,000 mg/m2 and leucovorin 300 mg/m2 ivd 24 hrs on D1,D8,\&D15) in chemotherapy-naïve patients with unresectable locally advanced, recurrent or metastatic gastric cancer. The treatment will be repeated every 28 days. The primary end-point is objective response rates evaluated by RECIST criteria, and the secondary end-points are overall survival, progression-free survival and safety profile. Approximately 41 patients will be enrolled in order to obtain the 37 evaluable patients required by Simon two-stage minimax design. All enrolled patients will be subjected to toxicity evaluations, but optionally to the correlative translational study of biomarkers in peripheral blood mononuclear cells. Patients with massive malignant ascites will optionally participate the study of biomarkers in neoplastic cells in ascites.