Breast Cancer Res Treat. 2009 May 21. [Epub ahead of print]
Results of a phase II open-label, nonrandomized trial of oral satraplatin in patients with metastatic breast cancer.
Smith JW 2nd, McIntyre KJ, Acevedo PV, Encarnacion CA, Tedesco KL, Wang Y, Asmar L, O'Shaughnessy JA.
US Oncology Research, Inc., The Woodlands, TX, USA, John.Smith@usoncology.com.
Cisplatin and carboplatin have antitumor activity in breast cancer. Satraplatin, an orally bioavailable platinum analog, offers a potential alternative to intravenous chemotherapy. We conducted a multicenter phase II study of this agent as first- or second-line treatment of metastatic breast cancer. Satraplatin 80 mg/m(2) was taken PO Days 1-5 q 21 days in cycles 1 and 2, and if tolerated, increased to 100 mg/m(2) for subsequent cycles. Restaging studies to assess response were performed after every 2 cycles.
Between November 2005 and March 2006, 40 patients were enrolled. Baseline characteristics: 48% prior adjuvant chemotherapy, 60% prior chemotherapy for MBC; median age, 62 years (ranges 43-83), 58% ER+/PR+, 23% ER+/PR-, 18% ER-/PR-/HER2-, and 5% HER2+. In 31 patients with measurable disease, there were two partial responses (PR; 6%; 95% CI 0, 15.2); and four patients (13%) had SD >/=6 months for a clinical benefit rate of 19%. Among the subanalysis of seven triple-negative patients with measurable disease, there were 2 SD and 2 PD.
Median survival was 15 months and median progression-free survival was 2.7 months. The most common grade 3-4 toxicities were neutropenia (28%) and thrombocytopenia (25%). AEs leading to treatment discontinuation were nausea (n = 3), thrombocytopenia (n = 3), fever (n = 2), and vomiting (n = 2). This phase II study demonstrates oral satraplatin has limited activity as a single agent for MBC. Satraplatin, at a lower dose used in this study, could be combined with other chemotherapy agents in future trials in breast cancer.