A phase 1/1b study of satraplatin (JM-216) in combination with docetaxel in patients with advanced solid tumors and metastatic castrate-resistant prostate cancer

Background: Satraplatin is an oral platinum with potential advantages over other platinum agents. This study investigated the combination of satraplatin and docetaxel in a phase 1 study of patients with advanced solid tumor malignancies followed by a phase 1b study in men with chemotherapy naïve metastatic castrate-resistant prostate cancer (CRPC). Methods:In this single institution phase 1/1b study, patients received docetaxel on day 1 and satraplatin on days 1-5 of a 21-day cycle ± granulocyte colony stimulating factor (GCSF). For phase 1b, prednisone 10 mg daily was added. Results:Twenty-nine patients received treatment. Based on 3 dose limiting toxicities (DLT) (grade 4 neutropenia) in 13 patients at dose levels 1 and -1 (docetaxel 60 mg/m2 plus satraplatin 40 mg/m2 and docetaxel 60 mg/m2 plus satraplatin 50 mg/m2) GCSF was administered with subsequent cohorts. A dose level of docetaxel 60 mg/m2 plus satraplatin 50 mg/m2 with GCSF was the starting dose level for phase 1b. At the highest dose in the phase 1b (docetaxel 75 mg/m2 plus satraplatin 50 mg/m2) there were no DLTs. Conclusion:The combination of satraplatin and docetaxel is feasible in solid tumor malignancies. In advanced malignancies, the recommended phase 2 dose is docetaxel 60 mg/m2 IV day 1 with satraplatin 40 mg/m2/d PO days 1-5, without G-CSF, and Docetaxel 70 mg/m2 IV day 1 with Satraplatin 50 mg/m2/day PO days 1-5, with G-CSF support, repeated in 3-week cycles. For patients with CRPC the recommended phase 2 dose is docetaxel 75 mg/m2 IV day 1 with satraplatin 50 mg/m2/d PO days 1-5, with G-CSF and prednisone 10 mg daily, repeated in 3-week cycles.