Phase II study of a cremophor-free, polymeric micelle formulation of paclitaxel for patients with advanced urothelial cancer previously treated with gemcitabine and platinum.

INTRODUCTION: Genexol-PM is a novel Cremophor® EL (CrEL)-free polymeric micelle formulation of paclitaxel. This multicenter phase II study was designed to evaluate the efficacy and safety of Genexol-PM monotherapy in patients with advanced urothelial carcinoma who developed disease progression after gemcitabine and cisplatin combination chemotherapy.

PATIENTS AND METHODS: Patients received Genexol-PM 240 mg/m(2) intravenously over 3 h every 3 weeks without premedication. Intra-patient dose escalation to 300 mg/m(2) was allowed during the second and subsequent cycles if pre-specified toxicities were not observed during the first cycle. The primary endpoint was response.

RESULTS: Thirty-seven patients were enrolled in this study. Platinum-free interval was less than 6 months in 27 (73%) patients, and 24 (64%) were categorized as having intermediate or poor prognosis according to Bajorin's criteria. Of 34 evaluable patients, there were 7 responses (21%; 95% CI, 7-34%), including one complete response (CR), with a median response duration of 6.5 months (95% CI, 3.5-9.6 months). The median time to progression was 2.7 months (95% CI, 0.9-4.6 months) with a median overall survival of 6.5 months (95% CI, 5.0-8.0 months). The most common grade 3/4 non-hematologic toxicities were peripheral neuropathy (sensory type 5.9%; motor type 8.8%) and infection (5.9%). Grade ≥3 hematologic toxicities occurred in only one patient.

CONCLUSION: Genexol-PM was generally well tolerated and demonstrated sufficient antitumor activity to warrant further development when used as second-line chemotherapy after gemcitabine-cisplatin failure in patients with urothelial carcinoma (NCT01426126).