Combination of Docetaxel Plus Savolitinib in Refractory Cancer Patients: A Report on Phase I Trial

MET amplification is a frequently observed genomic aberration in solid tumors. We conducted a phase I trial to evaluate dose-limiting toxicity (DLT) and recommended phase II dose (RP2D) for the combination therapy. The following dose levels were tested in this single-arm phase I study: docetaxel as an intravenous infusion over 1？hour at 60？mg/m2 once every 3？weeks of a 21-day schedule plus savolitinib (level 1, 200？mg qd; level 2, 400？mg qd; level 3, 600？mg qd; level 4800？mg qd). In total, there were 17 patients enrolled on to this study [7 gastric cancer (GC) patients, 5 melanoma patients, 3 sarcoma patients, and 2 rectal cancer patients]. Most of the patients (14 of 17) were heavily pretreated (≥third line or greater lines of treatment). For the first 3 cohorts (200？mg savolitinib + docetaxel 60？mg/m2, 400？mg savolitinib + docetaxel 60 mg/m2, 600？mg savolitinib + docetaxel 60？mg/m2), there were no DLTs. In the fourth dose cohort (800？mg savolitinib + docetaxel 60？mg/m2), one DLT occurred with generalized edema grade 3 that required intensive management. One GC patient with both MET overexpression (3+) and MET amplification (MET/CEP7 ratio, 7.3) achieved a durable partial response for 297？days, and another MET-amplified GC patient (MET/CEP7 ratio, 7.6) achieved stable disease for 86？days. Due to the higher incidence of G4 neutropenia in cohort 4 (800 mg), we recommend savolitinib 600？mg qd in combination with docetaxel 60？mg/m2 as the RP2D for phase II trial. The combination therapy demonstrated a very promising antitumor activity with durable responses in MET amplified GC patients