Abstract PS4-10-01: Neoadjuvant immune checkpoint inhibitors plus chemotherapy in early-stage triple-negative breast cancer: A systematic review and meta-analysis

Abstract Background Triple-negative breast cancer (TNBC) is an aggressive subtype with limited treatment options and poor prognosis. Immune checkpoint inhibitors (ICIs) have shown efficacy in the early-stage setting when combined with chemotherapy. We conducted a meta-analysis to evaluate their efficacy in terms of event-free survival (EFS), overall survival (OS), and pathological complete response (pCR). Methods We performed a systematic literature search of PubMed, Scopus, and ClinicalTrials.gov to identify randomized controlled trials comparing neoadjuvant or perioperative chemotherapy with or without ICIs in early-stage TNBC. Eligible trials reported on at least one of the following outcomes: EFS, OS, or pCR. Study selection, data extraction, and quality assessment were conducted independently by two reviewers, with discrepancies resolved by consensus. Hazard ratios (HRs) were pooled for EFS and OS using inverse-variance weighting. For pCR, both risk difference (RD) and risk ratio (RR) were calculated using Mantel-Haenszel methods. Heterogeneity was assessed using the I2 statistic. Pre-specified subgroup and sensitivity analyses were conducted, and publication bias was evaluated via funnel plot asymmetry. The study protocol was registered in PROSPERO (ID: CRD420251082981). Results Six phase II-III trials (KEYNOTE-522, IMpassion031, NeoTRIP Michelangelo, GeparNuevo, GeparDouze, CamRelief) comprising 3.952 patients were included. ICIs significantly improved EFS (HR = 0.76; 95% CI: 0.65-0.89; p = 0.0005; I2 = 3%) and OS (HR = 0.69; 95% CI: 0.57-0.84; p = 0.0002; I2 = 49%). For pCR, the absolute increase was 8% (RD = 0.08; 95% CI: 0.05-0.11; p < 0.00001; I2 = 0%), and the relative increase was 15% (RR = 1.15; 95% CI: 1.09-1.22; p < 0.00001; I2 = 3%). Notably, OS was not available in NeoTRIP and CamRelief, and EFS was not available in GeparNuevo. Sensitivity analyses (e.g., model selection) confirmed robustness. No evidence of publication bias was detected. Conclusion ICIs combined with chemotherapy significantly improve EFS, OS, and pCR in early-stage TNBC. These data support their incorporation into standard neoadjuvant treatment. Further studies should refine predictive biomarkers and long-term safety monitoring. Citation Format: S. Alexiou, M. Georgios, E. Saloustros. Neoadjuvant immune checkpoint inhibitors plus chemotherapy in early-stage triple-negative breast cancer: A systematic review and meta-analysis [abstract]. In: Proceedings of the San Antonio Breast Cancer Symposium 2025; 2025 Dec 9-12; San Antonio, TX. Philadelphia (PA): AACR; Clin Cancer Res 2026;32(4 Suppl):Abstract nr PS4-10-01.