Abstract P3-13-06: A prospective phase II trial of vinorelbine plus oxaliplatin in second- or third-line metastatic triple-negative breast cancer

Abstract

Abstract Purpose: Patients with metastatic triple-negative breast cancer (mTNBC) typically have a poor prognosis and limited treatment options. Previous study showed biweekly combination of vinorelbine and oxaliplatin (NVBOX) at doses of 30 mg/m2 and 90 mg/m2, respectively, is highly active and well tolerated as first-line treatment for patients with metastatic breast cancer. The purpose of this study (NCT 01528826) was to prospectively evaluate the efficacy and toxicity of NVBOX in second- or third-line mTNBC. Methods: Eligible patients were female with 18–70 years old and an Eastern Cooperative Oncology Group (ECOG) performance status of 0 to 1, and had mTNBC that had progressed after 1or 2 prior chemotherapy regimens in the metastatic setting. A period of 4 weeks (NVBOX twice) was considered as one treatment cycle and the maximum cycles were 6. The primary endpoint was progression-free survival (PFS). Secondary endpoints included overall survival (OS), objective response rate (ORR), and safety. Results: Between Dec 2011 and Nov 2012, forty-four patients were recruited [median age 47; 77.3% with viceral metastasis, 100% had been exposed to anthracyclines and/or taxanes; 56.8% cis/carbo-platin pretreated for MBC; 38.6% with time to progression (TTP) of 1-2 previous regimens before recruitment ≤ 3 months]. The overall response rate was 31.6% (1 complete response, 11 partial responses) and 10 achieved stable diseases (7 lasting more than 6 months) in 38 evaluable patients. After a median follow-up of 12.8 months, the median PFS and OS were 4.3 (95% CI, 3.6–5.0) months and 12.6 (95% CI, 8.1–17.0) months, respectively. PFS was significantly shorter in patients with disease free interval (DFI) ≤ 1year (HR = 2.10; 95% CI, 1.05–4.21; P = 0.037) and TTP of 1-2 previous regimens before recruitment ≤ 3 months (HR = 3.39; 95% CI, 1.66–6.89; P < 0.001). Also, these two factors were two independent predictors for the poor OS (HR = 5.45; 95% CI, 2.08–14.32; P < 0.001 and HR = 4.09; 95% CI, 1.73–9.68; P < 0.001). For 34 second line patients, prior platinum in the first line was a factor significantly compromise the PFS (HR = 2.29; 95% CI, 1.03–5.10; P = 0.043). Dose adjustment happened in 14 patients (31.8%) due to adverse events (AEs). Grade 3/4 hematologic toxicities were neutropenia (70.5%), thrombocytopenia (27.3%) and anemia (15.9%). Four patients experienced febrile neutropenia. The most frequent grade 3/4 non-hematologic toxicities were constipation (20.5%) and vomiting (11.4%). Two patients developed grade 3 NVBOX-related peripheral neurotoxicity. There were no treatment-related deaths. Conclusion: We conclude that biweekly NVBOX regimen is effective with a good safety profile in the second- or third-line mTNBC, which warrants further investigation in a phase III study. Citation Information: Cancer Res 2013;73(24 Suppl): Abstract nr P3-13-06.