A phase II trial in patients with metastatic triple-negative breast cancer (TNBC) found that first-line nab-paclitaxel plus carboplatin (nab-P/C) offered longer progression-free survival (PFS) than nab-paclitaxel plus gemcitabine (nab-P/G) or gemcitabine plus carboplatin (G/C).
“Metastatic TNBC is associated with a shorter median survival time vs metastatic disease from other types of breast tumors, and > 40% of patients with metastatic TNBC develop central nervous system metastases,” wrote study authors led by Denise A. Yardley, MD, of Tennessee Oncology in Nashville. Previous work has suggested that nab-paclitaxel–based regimens may offer improved activity in this patient population.
The tnAcity trial included 191 patients with metastatic TNBC randomized to receive nab-P/C (64 patients), nab-P/G (61 patients), or G/C (66 patients). The median age of patients was lower in the two nab-paclitaxel groups compared with the G/C group, and there were some differences with regard to race/ethnicity and disease-free interval, though generally the baseline characteristics of the groups were well balanced. The results of the study were published in Annals of Oncology.
The median PFS with nab-P/C was 8.3 months, compared with 5.5 months with nab-P/G, for a hazard ratio (HR) of 0.59 (95% CI, 0.38–0.92; P = .02). This was also longer than the G/C group (6.0 months), for an HR of 0.58 (95% CI, 0.37–0.90; P = .02). At 12 months, the PFS rate was 30% with nab-P/C, 13% with nab-P/G, and 11% with G/C.
The overall survival was numerically longer with the nab-P/C regimen, but this did not reach significance. The median overall survival was 16.8 months with nab-P/C, compared with 12.1 months with nab-P/G (HR, 0.73 [95% CI, 0.47–1.13]; P = .16) and 12.6 months with G/C (HR, 0.80 [95% CI, 0.52–1.22]; P = .29).
The objective response rate was 73% with nab-P/C, compared with 39% with nab-P/G and 44% with G/C. The median duration of response in the three groups was 6.2 months, 5.8 months, and 5.0 months, respectively.
There was at least one grade 3 or higher adverse event reported in 80% of nab-P/C patients, 77% of nab-P/G patients, and 84% of G/C patients. The grade 3 and higher adverse events were mainly hematologic, including neutropenia, anemia, and thrombocytopenia. Grade 3 or higher peripheral neuropathy was reported in 5%, 7%, and 2% of each group, respectively.
“TNBC is characterized by an aggressive clinical course and high tumor burden, with patients experiencing frequent relapses following a short disease-free interval, as well as visceral involvement,” the authors wrote. “Therefore, agents or regimens that may result in higher response rates to treatment may be incrementally more important for patients with TNBC compared with other breast cancer subtypes.” The new findings, they wrote, suggest that chemotherapy remains a viable option in this setting, and that nab-paclitaxel/carboplatin should be considered an option.