No standard first-line treatment exists for patients with metastatic triple-negative breast cancer (mTNBC). In this single-arm, phase II study (NCT00601159), we evaluated the efficacy and tolerability of cisplatin and gemcitabine (GP) as the first-line therapy in mTNBC. Eligible women were those who had measurable disease with no prior chemotherapy for mTNBC. All patients received 21-day-cycle of cisplatin 25 mg/m2 on days 1–3 and gemcitabine 1,000 mg/m2 on days 1 and 8. Treatment was continued until disease progression, unacceptable toxicity or up to 8 cycles. BRCA1/2 mutation status and immunohistochemical basal markers were included in the correlative studies. Sixty-four patients with the median age of 49 years were enrolled. Thirty patients (46.9%) had ≤1 year from diagnosis to recurrence. The median progression free survival (PFS) was 7.2 months (95%CI, 5.6–8.9 months) and overall survival (OS) was 19.1 months (95%CI, 12.4–25.8 months) with median follow-up 42 months. Patients received treatment for a median of six cycles. The overall response rate was 62.5%. The most common grades 3/4 toxicities were neutropenia (42.2%), thrombocytopenia (29.7%), anemia (18.8%) and nausea/vomiting (15.6%).No specific BRCA1/2 mutation carriers were identified. The efficacy of responses and basal-like subtype were independent favorable factors for PFS and OS, respectively. We conclude that the combination of GP has significant activity and a favorable safety profile as the first-line chemotherapy in mTNBC patients, in particular patients with basal-like subtype. The promising role of this combination as the front-line treatment for mTNBC continued to be evaluated in our ongoing phase III trial (CBCSG006).What's new?
Most chemotherapies for breast cancer target one of three receptors commonly found on the cell surface, but a significant number of tumors are triple-negative, expressing none of these. Treating these tumors can be difficult, particularly after metastasis, because no specifically targeted therapies yet exist. This study evaluated the drugs gemcitabine and cisplatin to see how they fared against this challenging cancer. The authors found that the synergistic drug combination was tolerated well by patients and effectively prolonged survival, suggesting this may be a promising treatment strategy.