To date, 60 patients have been enrolled in the Phase I trial with ARQ 197, a small molecule inhibitor of the c-Met receptor tyrosine kinase. No dose-limiting toxicity was observed, and a recommended Phase II dose of 120mg twice daily was established based on pharmacokinetic data.
In the Phase I trial, 18 of 19 (94.7%) patients treated with ARQ 197 for 12 weeks or longer did not develop detectable new metastatic lesions, while five of seven (71.4%) patients treated for seven to 12 weeks did not develop detectable new metastatic lesions. Based on these observations, ArQule is planning a Phase II clinical trial program.
To test the efficacy of ARQ 197 at preventing bone metastases, mice were implanted with human bone grafts and subsequently injected with breast cancer cells. Approximately 20% of mice treated with ARQ 197 showed metastases of these cells to the bone grafts, a marked reduction compared to the nearly 50% of mice in two other groups that showed metastases, one group treated with paclitaxel and one a control group. These findings demonstrate the potential of ARQ 197 as an anti-osteotropic, anti-metastasis drug, ArQule said.