Phase 1 clinical study of pegylated liposomal doxorubicin (JNS002) in Japanese patients with solid tumors

BACKGROUND: Pegylated liposomal doxorubicin (PLD, JNS002) is a formulation of doxorubicin encapsulated polyethylene-glycol coated liposomes with prolonged circulation time and unique toxicity profile. This phase 1 study was aimed at investigating the maximum tolerated dose (MTD), recommended dose, toxicity, pharmacokinetics, and antitumor activity in Japanese patients with solid tumors. METHODS: Patients with solid tumors not amenable to standard forms of treatment were eligible. PLD was administered as an intravenous infusion every 4 weeks. Dose escalation of PLD was planned from 30 to 60 mg/m(2) in 10 mg/m(2) increments. The pharmacokinetics of total doxorubicin (encapsulated plus non-encapsulated) in plasma were examined for the first cycle of treatment. RESULTS: Fifteen patients, aged 49-69 (median; 56) years with advanced solid tumors were enrolled. The major non-hematological toxicities were hand-foot syndrome (HFS), rash and stomatitis. Myelosuppression, especially leukopenia and neutropenia were major hematological toxicities. Although HFS was not severe, a delay of doses for subsequent cycles was required with multiple dosing. The peak plasma concentration and the area under the concentration time curve of PLD increased proportionally to the dose. Objective response was observed in one patient and the normalization of tumor marker values in another. These two patients had been diagnosed with ovarian cancer. CONCLUSION: The recommended dose for phase 2 clinical studies of PLD in Japanese patients was 50 mg/m(2) every 4 weeks. The encouraging results prompted us to plan a subsequent clinical study of PLD against ovarian cancer.