Phase I and pharmacokinetic study of aplidine, a new marine cyclodepsipeptide in patients with advanced malignancies

Purpose To establish the safety, pharmacokinetic parameters, maximum-tolerated dose, and recommended dose of aplidine, a novel marine cyclodepsipeptide, in patients with advanced cancer. Patients and Methods Using a modified Fibonacci method, we performed a phase I and pharmacokinetic study of aplidine administered as a 24-hour intravenous infusion every 2 weeks. Results Sixty-seven patients received aplidine at a dose ranging from 0.2 to 8 mg/m(2). Dose-limiting myotoxicity corresponding to grade 2 to 3 creatine phosphokinase elevation and grade 1 to 2 myalgia and muscle weakness occurred in two of six patients at 6 mg/m(2). No cardiac toxicity was Electron microscopy analysis showed the disappearance of thick filaments of myosin. observed. Grade 3 muscle toxicity occurred in three of 14 patients at the recommended dose of 5 mg/m(2) and seemed to be more readily reversible with oral carnitine (1 g/10 kg). Therefore, dose escalation was resumed using carnitine prophylactically, allowing an increase in the recommended dose to 7 mg/m(2). Other toxicities were nausea and vomiting, diarrhea, asthenia, and transaminase elevation with mild hematologic toxicity. Aplidine displayed a long half-life (21 to 44 hours), low clearance (45 to 49 L/h), and a high volume of distribution (1,036 to 1,124 L) with high interpatient variability in plasma, whereas in whole blood, clearance ranged from 3.0 to 6.2 L/h. Minor responses and prolonged tumor stabilizations were observed in patients with medullary thyroid carcinoma. Conclusion Muscle toxicity was dose limiting in this study. Recommended doses of aplidine were 5 and 7 mg/m(2) without and with carnitine, respectively. The role of carnitine will be further explored in phase II studies.