CD8-guided immunochemotherapy improves pathological complete response rates in high-tumor-burden triple-negative...

Blockade of the programmed cell death 1 ligand 1 (PD-L1) enhances the efficacy of standard chemotherapy in the neoadjuvant treatment of triple-negative early breast cancer (TNBC) but is associated with adverse events. This phase 2 trial evaluated camrelizumab (anti-PD-1) combined with chemotherapy in locally advanced immunomodulatory TNBC (CD8⁺ T cell infiltration ≥10%). From October 2022 to September 2023, 90 stage II-III TNBC patients were randomized to receive neoadjuvant chemotherapy ± camrelizumab (200 mg biweekly). The camrelizumab plus chemotherapy group (n = 45) achieved a pathological complete response (pCR) rate of 62.2% (95% confidence interval [CI]: 46.5%-76.2%) versus 42.2% (95% CI: 27.7%-57.8%) in the chemotherapy-alone group (n = 45), with a 20.0% absolute increase (p = 0.059). Grade ≥3 adverse events occurred in 88.9% (40/45) and 82.2% (37/45) of patients, respectively. Multi-omics analyses demonstrated significantly elevated CD8⁺ T cell infiltration in camrelizumab-treated pCR patients, alongside strong correlations between PD-L1 expression, stromal tumor-infiltrating lymphocytes, and CD8⁺ density. These results indicate that CD8-guided immunochemotherapy with camrelizumab improves pCR rates in high-tumor-burden TNBC with manageable toxicity, supporting CD8⁺ T cell levels as a predictive biomarker for immunotherapy response.