Comparative efficacy of anthracycline-free and anthracycline-containing neoadjuvant chemoimmunotherapy regimens for triple-negative breast cancer.

Background: The selection of appropriate chemotherapy backbone agents in combination with neoadjuvant immunotherapy for triple-negative breast cancer (TNBC) remains unclear. Herein, we aimed to evaluate the efficacy and safety of anthracycline-free and anthracycline-containing regimens coupled with neoadjuvant immunotherapy.

Method: This retrospective study included 87 patients with TBNC who received neoadjuvant immunotherapy combined with various chemotherapy regimens at three research centers from November 2020 to November 2023. The primary objective was pathological complete response (pCR), while secondary objectives included overall response rates, event-free survival (EFS), and the incidence of adverse events. A subgroup analysis was performed to delineate patients who may substantially benefit from distinct therapeutic strategies.

Results: Coupled with immunotherapy, anthracycline-free regimens achieved comparable pCR rates (55.1 % vs. 51.4 %; Odds ratio, 1.16; 95 % confidence interval [CI], 0.49-2.74; p = 0.73) and EFS (Hazard ratio, 0.66; 95 % CI, 0.18-2.45; p = 0.53) to anthracycline-containing regimens. According to subgroup analyses, the tumor stage (p = 0.017) and lymph node stage (p = 0.011) exhibit contradictory predictive power for the pCR rate of anthracycline-free regimens when compared with that of anthracycline-containing regimens. Specifically, anthracycline-free regimens yielded significantly higher pCR rates in patients without lymph node metastasis than anthracycline-containing regimens (p = 0.021). Pooled analyses further confirmed the results of both total and subgroup analyses. Most adverse events were grades 1-2, and no new adverse reactions were observed.

Conclusion: Anthracycline-free neoadjuvant chemotherapy regimens could serve as an effective and safe alternative immunotherapy partner for patients with TNBC, particularly in those without lymph node metastasis.