Neoadjuvant nivolumab plus paclitaxel/cisplatin- chemo-radiotherapy (neo-NTP-CRT) followed by esophagectomy for locally advanced esophageal squamous cell carcinoma (ESCC): A phase II study.

e16098 Background: Adjuvant nivolumab has shown efficacy in reducing recurrence in patients (pts) with locoregional esophageal cancer harboring pathologic residual disease following neoadjuvant chemoradiotherapy (CRT). However, the efficacy of adding nivolumab to neoadjuvant CRT remains unclear. Methods: We conducted a phase II trial of neoadjuvant nivolumab (240mg IV on D-14, 1, 15, 29), paclitaxel (50mg/m 2 IV on D1, 8, 15, 22, 29), cisplatin (30mg/m 2 IV on D1, 8, 15, 22, 29) and RT (45Gy given in 25 fractions) followed by esophagectomy 6 to 8 weeks after finishing CRT in pts with locally advanced ESCC, defined as clinical stage cT3-4aN0M0 or cT1-3N1-3M0 according to the AJCC Cancer Staging System 8 th ed. (ClinicalTrials.gov Identifier: NCT05130684). The study, in a Simon’s two-stage design, used pathological complete response (pCR) rate as the primary endpoint. Secondary endpoints included feasibility, safety, recurrence free survival (RFS), progression free survival (PFS), and overall survival (OS). Results: Between Jan 2021 and Apr 2023, we enrolled a total of 17 pts. Fifteen were male. The median age was 52 years (range: 44~69). The clinical stage was I, II, and III in 1, 1, and 15 pts, respectively. All pts received neo-NTP-CRT with the following dose-intensities (mean dose intensity range): nivolumab (95% 50%~ 100%), paclitaxel (75% 48%~ 100%, cisplatin (97% 80%~ 100%), and radiotherapy (100%). Fourteen pts received esophagectomy, and 4 of them achieved pCR (24%). Because pCR for the first stage did not meet the efficacy criteria to move forward to second-stage, the enrollment was discontinued after enrolling 17 pts. During neo-NTP-CRT, the most common treatment-related adverse events (TRAEs) were leukopenia (76%), neutropenia (59%), thrombocytopenia (35%), and skin rash (35%); and the most common grade 3 and 4 TRAEs were leukopenia (24%), neutropenia (6%), and nausea and vomiting (6%). Among 14 pts receiving esophagectomy, 4 experienced surgical complications, including 2 with anastomotic leakage, 1 with subclavian artery rupture, and 1 with pneumonitis; one pt died 263 days after surgery, followed by a prolonged hospital stay due to refractory anastomotic leakage, infectious complications, and tumor progression. The median follow-up duration was 18 months. Median RFS, PFS and OS was 8, 12, and 16 months, respectively. Conclusions: Our data indicate that adding nivolumab to neoadjuvant paclitaxel and cisplatin-based CRT is feasible but does not improve pCR rate in locally advanced ESCC pts. Clinical trial information: NCT05130684 .