A pilot study of sunitinib in Chinese patients with heavily pretreated metastatic breast cancer.

Abstract

e11506 Background: Sunitinib malate, an oral multitargeted tyrosine kinase inhibitor has shown antitumor activity in metastatic breast cancer. This study was conducted to evaluate the efficacy and safety of single-agent sunitinib in chinese breast cancer patients with multiple-resistant to antitumor drugs. Methods: Metastatic breast cancer patients with multiple-resistant to antitumor drugs received the treatment with single-agent sunitinib at dose 50 mg/d in 6-week cycles (4 weeks on, then 2 weeks off treatment), and toxicity-related dose reduction was permitted. The primary end point was objective response rate, and the second end point was the safety. Results: 29 patients were enrolled, the median age was 45 (27-68) ys, the median previous chemotherapy lines was 7 (3-17), 15 patients were ER/PR negative, 14 patients were ER/PR positive, 8 patients were HER-2 positive. 10 patients received a starting dose of sunitinib orally 50mg/d in 6-week cycles schedule, all patients had the dose reduction because of severe hematologic toxicity. So the following 19 patients received a starting dose of sunitinib orally 37.5mg/d schedule. The most frequent nonhematologic toxicity were yellow skin (100%), fatigue (82.8%), and hypertention (34.5%). Grade 3/4 hematologic toxicity included neutropenia (82.8%), thrombocyte decrease (79.3%). Of the 25 patients with measurable disease at baseline, 4 patients achieved a partial response (16%), 10 additional patients (40%) maintained stable disease for more than 10 weeks. Median time to progression and overall survival were 10 and 32 weeks, respectively. Notably, all the responses occurred in patients with a tumor ulcer. The median follow-up time was 26 (6-52) weeks, 4 patients were lost,17 patients were dead, and 8 patients were alive with metastatic disease. Conclusions: These data indicate that sunitinib has the sure activity in the chinene patients with pretreated metastatic breast cancer, especially in tumor ulcer. The recommended sutent monotherapy regimen was administered orally at 37.5mg/d in chinese breast cancer patients, and the major treatment-related adverse effects was hematologic toxicity.