Background: Vinorelbine (VI) and paclitaxel (TA) are among the most active single agents in the treatment of patients with breast carcinoma, and both have microtubules as their cytotoxic target. This Phase I-II study combined these 2 agents and used a 96-hour intravenous (i.v.) infusion of paclitaxel to maximize their cytotoxic activities.
Methods: Patients with metastatic breast carcinoma who were previously treated with chemotherapy were administered increasing doses of a 96-hour paclitaxel i.v. infusion from Days 1 to 5, with a first fixed dose of vinorelbine (12.5 mg/m(2) on Days 1 and 5) every 3 weeks. The dose of paclitaxel was then decreased starting from the previously established tolerated dose, and a second fixed dose of vinorelbine (15 mg/m(2) on Days 1 and 5) was given. This identified 2 acceptable doses of paclitaxel (110 mg/m(2) with VI 12.5 mg/m(2) and 90 mg/m(2) with VI 15 mg/m(2)). The latter was used in the subsequent Phase II study.
Results: For the 50 patients treated with any dose, the complete response (CR) and the CR plus partial response (PR) rates were, respectively, 14% and 48% (95% confidence interval [CI], 34-67%). When only the 27 patients treated with the Phase II dose were considered, the figures were, respectively, 11% and 52% (95% CI, 42-62%). The median time to progression was 26 weeks, and the median survival 51 weeks. The dose-limiting toxicity was febrile neutropenia.
Conclusions: At the dose schedule identified for the Phase II study, the VI-TA-96 combination has considerable antitumor activity; pharmacoeconomic interest (it requires about half the doses of the agents administered singly); no major toxicity, except G4 neutropenia; and no need for premedication. This combination may be recommended as one of the most effective therapeutic options for patients with metastatic breast carcinoma who were pretreated mainly with anthracycline-containing chemotherapy.
Copyright 2000 American Cancer Society.