A propensity-matched cohort study of neoadjuvant immunotherapy combined with chemotherapy versus neoadjuvant chemotherapy for early-stage triple-negative breast cancer.

e13134 Background: Preferred neoadjuvant treatment (NAT) regimens for early-stage triple-negative breast cancer (TNBC) include anthracycline-cyclophosphamide and taxane-based chemotherapy. This study compared the efficacy, safety and biomarker exploration of camrelizumab combined with chemotherapy and chemotherapy as neoadjuvant treatment for early-stage TNBC. Methods: This study included 2 cohorts with different NAT regimens, matched (2: 1) according to age, clinical T and N stage, and Ki-67 status. Patients in the immune combination chemotherapy (NIC) cohort were recruited from a phase II clinical trial (NCT04676997). NIC patients received intravenous camrelizumab at a dose of 200mg and simultaneous chemotherapy consisted of platinum-free drugs, or platinum containing drugs. Patients in the neoadjuvant chemotherapy (NAC) cohort regimen comprised 4 cycles of paclitaxel 175 mg/m2, and 4 cycles of epirubicin (90 mg/m2, d1, q2w) + cyclophosphamide (600 mg/m2, d1, q2w). The indicators of this study include pCR, breast pCR (bpCR), axillary lymph node dissection (ALND) rate, breast conserving surgery (BCS) rate and tumor immune microenvironment (TIME) analysis of gene expression profiling. Results: Of 252 eligible patients, 162 patients were identified in the analysis after propensity score matching (PSM). Compared with NAC alone, the addition of camrelizumab brought higher pCR rates (64. 81% versus 37. 04%, p<0. 05), ALND rates (38. 89% versus 12. 96%, p<0. 05) and comparable BCS rates (20. 37% versus 15. 74%, p<0. 05). Gene expression analysis was performed on tumor tissue samples from 12 patients receiving NAC and 16 patients receiving NIC before and after NAT. The results showed that the TIME status of the NIC and NAC groups before treatment was basically the same. Moreover, we respectively compared the TIME status of patients with pCR and nonₚCR in NIC and NAC before NAT. The results found that there were 9 significantly different signatures (p<0. 05) between pCR and nonₚCR patients in the NIC group, and 1 signature (p<0. 05) in the NAC group, respectively. Notably, we found 8 signatures (B Cells, CD8 T Cells, TIS, IFN Gamma, Lymphoid, T Cell, APM, Immunoproteasome), that were scored significantly higher only in pCR patients in the NIC group compared with non-pCR patients, and 8 signatures could promote response to immunotherapy. The common difference signature between the two groups is Treg cells. Conclusions: In patients with early-stage TNBC, neoadjuvant treatment with camrelizumab plus chemotherapy significantly improved pCR with an acceptable safety profile. Differences in TIME may affect response to treatment regimens. Future validation in prospective randomized controlled trials with larger sample sizes is needed. Clinical trial information: NCT04676997.