nab-Paclitaxel plus carboplatin or gemcitabine versus gemcitabine plus carboplatin as first-line treatment of patients with triple-negative metastatic breast cancer: results from the tnAcity trial

Background: Metastatic triple-negative breast cancer (mTNBC) has a poor prognosis and aggressive clinical course. tnAcity evaluated the efficacy and safety of first-line nab-paclitaxel plus carboplatin (nab-P/C), nab-paclitaxel plus gemcitabine (nab-P/G), and gemcitabine plus carboplatin (G/C) in patients with mTNBC. Patients and methods: Patients with pathologically confirmed mTNBC and no prior chemotherapy for metastatic BC received (1 : 1 : 1) nab-P 125 mg/m(2) plus C AUC 2, nab-P 125 mg/m(2) plus G 1000 mg/m(2), or G 1000 mg/m(2) plus C AUC 2, all on days 1, 8 q3w. Phase II primary end point: investigator-assessed progression-free survival (PFS); secondary end points included overall response rate (ORR), overall survival (OS), percentage of patients initiating cycle 6 with doublet therapy, and safety. Results: In total, 191 patients were enrolled (nab-P/C, n = 64; nab-P/G, n = 61; G/C, n = 66). PFS was significantly longer with nab-P/C versus nab-P/G [median, 8.3 versus 5.5 months; hazard ratio (HR), 0.59 [95% CI, 0.38-0.92]; P = 0.02] or G/C (median, 8.3 versus 6.0 months; HR, 0.58 [95% CI, 0.37-0.90]; P = 0.02). OS was numerically longer with nab-P/C versus nab-P/G (median, 16.8 versus 12.1 months; HR, 0.73 [95% CI, 0.47-1.13]; P = 0.16) or G/C (median, 16.8 versus 12.6 months; HR, 0.80 [95% CI, 0.52-1.22]; P = 0.29). ORR was 73%, 39%, and 44%, respectively. In the nab-P/C, nab-P/G, and G/C groups, 64%, 56%, and 50% of patients initiated cycle 6 with a doublet. Grade >= 3 adverse events were mainly hematologic . Conclusions: First-line nab-P/C was active in mTNBC and resulted in a significantly longer PFS and improved risk/benefit profile versus nab-P/G or G/C.