According to a phase 3 trial, adding carboplatin to a standard adjuvant chemotherapy regimen of dose-dense doxorubicin and cyclophosphamide (AC) followed by paclitaxel (P) did not significantly improve invasive disease-free survival (IDFS) in patients with operable node-positive or high-risk node-negative triple-negative breast cancer (TNBC).

These results will first be presented by Vicente Valero, MD, The University of Texas MD Anderson Cancer Center, Houston, Texas, at the 2025 American Society of Clinical Oncology (ASCO) Annual Meeting at Chicago, Illinois.

Between June 2015 and May 2022, 769 patients were randomized to receive doxorubicin and cyclophosphamide followed by weekly paclitaxel as a control group (n=385) or the same regimen plus carboplatin 5 every 3 weeks for 4 cycles (n=384). Eligible patients had operable TNBC with either node-positive disease or high-risk node-negative disease. Patients were stratified by  nodal status and germline BRCA (gBRCA) mutation status.

The primary end point was IDFS with a hazard ratio (HR) of 0.67. Secondary end points included distant recurrence-free interval (DRFI), overall survival (OS), breast cancer-free survival (BCFS), and relapse-free survival (RFS).

Overall, the median follow up was 79.4 months. Among patients in the control group, IDFS events occurred in 23.9% patients, which was higher than patients treated with additional carboplatin (19.8%, P = .097). The HR for IDFS was 0.77 (95% confidence interval [CI], 0.57 to 1.05), with 5-year IDFS rates of 77.8% (95% CI, 73.7 to 82.2) in the control group and 82.9% (95% CI, 79.2 to 86.9) in the additional carboplatin group.

The control group demonstrated lower 5-ear DRFI than patients in the additional carboplatin group (84.4%; 95% CI, 80.7 to 88.2 vs 88.7%; 95 % CI, 85.5 to 92.0). In terms of survival, the 5-year OS was also lower among the control group than patients in the additional carboplatin group (84.4%; 95% CI, 80.8 to 88.3 vs 87.7%; 95% CI, 84.4 to 91.2).

Grade ≥3 treatment-related adverse events were more frequent in the carboplatin group (72.9%) compared to the control group (51.1%), though rates of grade 5 events were similar (0.8% in both arms).

"The addition of carboplatin to paclitaxel following dose-dense AC did not result in a statistically significant improvement in IDFS, DRFI, or OS," the investigators concluded. "However, the observed trend toward improved IDFS supports future translational research to identify patient subsets who may benefit from carboplatin-based adjuvant therapy."

Source:

Valero V, Rang G, Rastogi P, et al. NRG-BR003: A randomized phase III trial comparing doxorubicin plus cyclophosphamide followed by weekly paclitaxel with or without carboplatin for node-positive or high-risk node-negative TNBC. Presented at 2025 ASCO Annual Meeting. May 30-June 3, 2025; Chicago, IL. Abstract LBA509.