nab-Paclitaxel Plus Carboplatin or Gemcitabine vs Gemcitabine Plus Carboplatin as First-Line Treatment for Patients With Triple-Negative Metastatic Breast Cancer: Results From the tnAcity Trial

Abstract

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/m² plus C AUC 2, nab-P 125 mg/m² plus G 1000 mg/m², or G 1000 mg/m² plus C AUC 2, all on days 1, 8 q3w. Phase II primary endpoint: investigator-assessed progression-free survival (PFS); secondary endpoints 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 vs nab-P/G (median, 8.3 vs 5.5 months; HR, 0.59 [95% CI, 0.38-0.92]; P = .02) or G/C (median, 8.3 vs 6.0 months; HR, 0.58 [95% CI, 0.37-0.90]; P = .02). OS was numerically longer with nab-P/C vs nab-P/G (median, 16.8 vs 12.1 months; HR, 0.73 [95% CI, 0.47-1.13]; P = .16) or G/C (median, 16.8 vs 12.6 months; HR, 0.80 [95% CI, 0.52-1.22]; P = .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 vs nab-P/G or G/C.