P5-19-04: Results of a Randomized Phase II Study Demonstrate Benefit of Platinum-Based Regimen in the First-Line Treatment of Triple Negative Breast Cancer (TNBC).

Abstract

Background: It is supposed that triple negative breast cancer (TNBC) may be more sensitive to DNA damage agents such as platinum. This study was designed to compare platinum-based regimen (docetaxel plus cisplatin) with non-platinum-based regimen (docetaxel plus capecitabine) in the first-line treatment of advanced triple negative breast cancer patients. Patients and Methods: This was a single-institution, randomized phase II clinical trial. Eligible TNBC women with first relapse or metastasis who had measurable disease were randomized (1:1) to receive either TP regimen (docetaxel 75mg/m2 plus cisplatin 75mg/m2 intravenous infusion day 1) or TX regimen (docetaxel 75mg/m2 intravenous infusion day 1 plus capecitabine 1000mg/m2 bid, two weeks on, one week off) every 3 weeks for up to 6 cycles, until disease progression, unacceptable toxicity or patient consent withdrawal. The primary endpoint was objective response rate (ORR) and secondary endpoints included progression free survival (PFS), overall survival (OS) and safety profile. To detect a difference of 0.35 in response rate between groups with a power of 80% and 2-sided significance level at 0.05, there should be at least 26 patients in each group. As of Jun 1st, 2011, 53 patients had been randomized and evaluated. Results: After a median follow-up of 24 months, the results showed much higher response rate in TP group than TX group although the clinical benefit rate was not significantly different. PFS was more than doubled in TP group compared with TX group. Overall survival was also statistically improved. G3/4 vomiting was merely observed in 3 patients from TP group. On the contrary, only patients in TX group (5/26) reported G2/3 Hand-Foot Syndrome. No differences were found in hematological and other non-hematological toxicities. Conclusions: Although it is a small sample size phase II study, it strongly suggested that cisplatin-contained TP regimen improved patient outcome, as measured by ORR, CBR, PFS and OS, compared with non-cisplatin-based TX regimen in the first-line treatment of advanced TNBC patients. This is the first prospective study to show superiority of cisplatin over capecitabine in TNBC. Together with additional ongoing clinical trials comparing platinum with other chemotherapeutic agents in various settings, the role of platinum in TNBC can be further elucidated. Citation Information: Cancer Res 2011;71(24 Suppl):Abstract nr P5-19-04.