Phase I Trial of Arginine Deprivation Therapy with ADI-PEG 20 Plus Docetaxel in Patients with Advanced Malignant Solid Tumors.

PURPOSE: This phase I study examined the toxicity and tolerability of pegylated arginine deiminase (ADI-PEG 20) in combination with docetaxel in patients with advanced solid malignancies. EXPERIMENTAL DESIGN: Eligible patients had histologically proven advanced solid malignancies, with any number of prior therapies, Zubrod performance status 0-2, and adequate organ function. Patients received ADI-PEG 20 weekly intramuscular injection ranging from 4.5 to 36 mg/m(2) and up to 10 doses of docetaxel (75 mg/m(2)) every 3 weeks. Primary endpoints were safety, toxicity, and a recommended phase II dose. Circulating arginine levels were measured before each cycle. Tumor response was measured as a secondary endpoint every 6 weeks on study. RESULTS: Eighteen patients received a total of 116 cycles of therapy through four dose levels of ADI-PEG 20. A single dose-limiting toxicity (grade 3 urticarial rash) was observed at the 1st dose level, with no additional dose-limiting toxicities observed. Hematologic toxicities were common with 14 patients experiencing at least one grade 3 to 4 leukopenia. Fatigue was the most prevalent toxicity reported by 16 patients. Arginine was variably suppressed with 10 patients achieving at least a 50% reduction in baseline values. In 14 patients with evaluable disease, four partial responses (including 2 patients with PSA response) were documented, and 7 patients had stable disease. CONCLUSIONS: ADI-PEG 20 demonstrated reasonable toxicity in combination with docetaxel. Promising clinical activity was noted, and expansion cohorts are now accruing for both castrate-resistant prostate cancer and non-small cell lung cancer at a recommended phase II dose of 36 mg/m(2).

Phase I study of the combination of temsirolimus and pazopanib in advanced solid tumors.

Inhibition of either vascular endothelial growth factor receptor or mammalian target of rapamycin (mTOR) signaling improves outcomes in patients with several advanced solid tumors. We conducted a phase I trial of temsirolimus with pazopanib to investigate the feasibility of simultaneous 'vertical inhibition' of vascular endothelial growth factor receptor and mTOR pathways. Patients with advanced solid tumors, no previous pazopanib or mTOR inhibitor, good performance status, and acceptable end-organ function were eligible. In a typical 3+3 escalation design starting at temsirolimus 15 mg by an intravenous infusion weekly and pazopanib 400 mg orally daily, we defined dose-limiting toxicity (DLT) as attributable grade 3 or higher nonhematologic adverse events in the first 28-day cycle and the maximum tolerable dose as the maximum dose level at which less than two patients experienced DLT. At the initial dose level, two patients had four DLTs (anorexia, fatigue, hyponatremia, and hypophosphatemia). After reduction to temsirolimus 10 mg intravenous infusion weekly and pazopanib 200 mg orally daily, one of three patients had DLT (fatigue) and the first patient in the subsequent expansion had dose-limiting hypophosphatemia. Attributable grade 3 or higher adverse events in more than one patient included leukopenia, neutropenia, fatigue, and hypophosphatemia. Tumor reduction not fulfilling the RECIST criteria for partial response was the best response in four of seven evaluable patients. The combination of temsirolimus and pazopanib was not feasible at clinically meaningful doses in this population because of constitutional and electrolyte disturbances.