360PDGEMCITABINE WITH CISPLATIN OR PACLITAXEL IN METASTATIC TRIPLE-NEGATIVE BREAST CANCER.

ABSTRACT Aim: There is still no standard first-line chemotherapy for patients with metastatic triple-negative breast cancer (mTNBC). This study compared the first-line use of gemcitabine/cisplatin (GP) with one standard regimen containing gemcitabine/paclitaxel (GT) for patients with mTNBC in terms of efficacy and safety. Methods: A hybrid trial design incorporating a formal test of superiority as well as non-inferiority was applied to compare the GP and GT regimens as first-line treatment on PFS of mTNBC in the Chinese Breast Cancer Study Group (CBCSG) 006 trial (clinicaltrials.gov Identifier: NCT01287624).We randomly assigned 240 mTNBC patients with no previous exposure to palliative chemotherapy to receive GP regimen (1250 mg/m2 d1,8/ 75 mg/m2 d1) or GT regimen (1250 mg/m2 d1,8 /175 mg/m2 d1) with expected median PFS improvement of 1.2 months. Results: Between Jan. 2011 and Nov. 2013, 236 patients received at least one dose of assigned chemotherapy with 118 patients in each arm and were all put in the intent-to-treat analysis. As of Mar. 20, 2014, there were 201 PFS events and 97 overall survival events. The GP regimen was different from the GT regimen in terms of objective response rates (67.9% vs. 50.4%, P= 0.008), PFS (median 232 vs.194 days, P= 0.009; HR 0.692, 95%CI 0.523-0.915), and overall survival (median 672 vs.556 days, P= 0.611). Delivered relative dose intensity for the three drugs was all more than 90%, with the number of total delivered cycles per arm at 654 and 648 for GP and GT, respectively. Significant differences in grade 3/4 adverse events between the GP and GT arms were nausea (6.8% and 0.8%), vomiting (11.0% and 0.8%), anemia (33.1% and 5.1%), thrombocytopenia (32.2% and 2.5%). For adverse events of all grades, the GP regimen had significantly more nausea, vomiting, anorexia, constipation, hypomagnesemia, hypokalemia, anemia, and thrombocytopenia while GT regimen had significantly more alopecia and peripheral neuropathy. Conclusions: The GP regimen is better than the GT regimen in terms of objective response and PFS in the first-line treatment of mTNBC patients. The toxicity profiles of the two regimens were different without any unexpected findings. Disclosure: All authors have declared no conflicts of interest.