Neoadjuvant therapy of camrelizumab combined with chemotherapy in patients (pts) with resectable esophageal squamous cell cancer (ESCC): A single-center, single-arm, exploratory clinical trial.

e16095 Background: The study aimed to evaluate the efficacy and safety of neoadjuvant therapy of camrelizumab, combined with chemotherapy in resectable ESCC pts and explore factors related to efficacy. Methods: Patient with resectable ESCC, staged as cT1b-cT2N+ or cT3-cT4aNany were enrolled. Eligible pts received camrelizumab (200 mg, d1) combined with nab-paclitaxel (200 mg/m 2 , d1) and nedaplatin (75 mg/m 2 , administered on an average of two days) and S-1 (50mg/m 2 , bid, d1-14) for 2 or 3 cycles (21 days per cycle) before surgery. The primary endpoints were pathological complete response (pCR) rate. Results: From Aug 25, 2022, to Nov 17, 2023, a total of 53 pts were enrolled in this study and completed 2 or 3-cycle neoadjuvant therapy. Median age was 58(54-63), 47 males and 6 females, The primary site was upper segment in 3 pts, middle segment in 27 pts, and lower segment in 23 pts, The clinical T staging was T2 in 2 pts, T3 in 49 pts, and T4 in 2 pts. The clinical N staging was N0 in 8 pts, N1 in 28 pts, N2 in 16 pts, and N3 in 1 pt. The physical condition score was 0 for 16 pts, and 1 for 27 pts. 37 pts underwent surgery and R0 recetion was achieved in 37 (100%) pts. pCR(ypT0N0) was identified in 9(24.3%) and 3(8.1%) pts had conplete response of primary tumor but residual didease in lymph nodes alone (ypT0N+), the MPR was was identified in 5(13.5%) pts. Of pts who underwent surgery, 25(67.6%) received 3-cycle and 12(32.4%) received 2-cycle neoadjuvant therapy, the pCR rate was 32% and 8.3%,respectively. According to tumor regression grade, 12 (11(44%) in 3-cycle and 1(8.3%) in 2-cycle) pts had TRG0, 5(4(16%) in 3-cycle and 1(8.3%) in 2-cycle) TRG1, 15 (9(36%) in 3-cycle and 6(50%) in 2-cycle) TRG2, and 4 (all 4(33.3%) in 2-cycle) TRG3. Also we found there was no relationship between the NK cells, B cells, total T lymphocytes, Th cells, Tc/Ts cells, CD4+/CD8+ratio and the pCR and MPR rate. The most common AEs were anemia (71.7%)、 lymphocyte count decreased (67.9%)、white blood cell count decreased (52.8%) and neutrophil count decreased (52.8%). Most AEs were grade 1-2. No grade 4/5 AEs occurred. Conclusions: The short-term efficacy and safety of camrelizumab combined with three drugs chemotherapy were similar to previous research combined with two drugs.The efficacy of three-cycle regimen seems to be significantly better than the two-cycle regimen, which may indicate that the two-cycle neoadjuvant therapy is still insufficient, and confirmatory results need to be verified through large-scale clinical studies. Clinical trial information: ChiCTR2300068185.