Efficacy of nimotuzumab combined with concurrent chemoradiotherapy for patients with postoperative loco-regional recurrent esophageal squamous cell carcinoma: A phase II study.

4067 Background: The clinical therapeutic effect for patients with postoperative loco-regional recurrent esophageal squamous cell carcinoma (ESCC) is not satisfactory. Nimotuzumab, an EGFR-targeted humanized antibody, showed efficacy in the treatment of ESCC. We explored the efficacy of nimotuzumab combined with concurrent chemoradiotherapy (CCRT) for patients with postoperative loco-regional recurrent ESCC. Methods: Eligible patients (18-75 years) with postoperative loco-regional recurrent ESCC were enrolled in this single-arm phase II study, received nimotuzumab (400mg on D1, 200mg/w for 6 weeks) combined with CCRT (chemotherapy:TP regimen, radiotherapy: 45-50.4Gy/25-28f/5-6w), sequentially nimotuzumab 200mg every 3 weeks plus chemotherapy (patients with partial response or stable disease). The primary endpoint was objective response rate (ORR), the second endpoints were disease control rate (DCR), overall survival (OS), progression-free survival (PFS), and local-regional control (LRC) and adverse events. Results: From Sep 2021 to Apr 2024, 44 patients were screened, ultimately 42 patients were included in the Full Analysis set. The median age was 69 years (range: 48-75). 12 (28.57%) patients achieved complete response, 24 (57.14%) patients with partial response, 5 (11.90%) patients with stable disease, and 1 (2.38%) patient with progressive disease. ORR was 85.71%, and DCR was 97.62%. The failure patterns showed that 10 (23.81%) patients had loco-regional recurrence, and 9 (21.43%) had distant metastases after CCRT. The median follow-up was 29.3 months (95%CI: 25.7-38.0). 3-year OS was 51.8% (95%CI: 36.9-72.8%), with the median OS was not reached. 3-year PFS was 33.4% (95%CI: 20.4-54.7%), and the median PFS was 15.1 months (95%CI: 11.8-NE), 3-year LRC was 46.1% (95%CI: 29.9-71.0%), the median LRC was 30.8 (95%CI: 16.6-NE). The most common Graded 3-5 adverse events (AEs) included leukopenia, thrombocytopenia, hemoglobin decreased, radiation esophagitis, radiation-induced lung injury, fatigue, and radiodermatitis. 4 patients experienced Grade 3-5 radiation esophagitis, in which 2 patients developed esophageal fistulas (1 patient died). No nimotuzumab-related serious AEs occurred. Conclusions: Nimotuzumab combined with CCRT showed promising ORR and survival with tolerable toxicity in patients with postoperative loco-regional recurrent ESCC. Clinical trial information: ChiCTR2200063875.