Phase 2 study of nimotuzumab with concurrent curative radiotherapy and S-1 for stage II-IVB ESCC in patients aged 75 years or older

Concurrent chemoradiotherapy is the standard treatment for inoperable, locally advanced esophageal squamous cell carcinoma (ESCC). Elderly patients often have reduced tolerance to this treatment. A phase 2 trial at Nanjing Medical University (China) evaluated the EGFR antagonist nimotuzumab combined with concurrent radiotherapy and S-1 for ESCC in patients aged 75 year or older. A total of 56 patients were enrolled, with the primary endpoint being progression-free survival (PFS), while secondary endpoints included overall survival (OS), objective response rate (ORR), disease control rate (DCR), treatment-related adverse events (TRAEs), nutritional indicators, and quality of life (QOL). Most nutritional indicators remained stable after treatment. The median duration of follow-up was 24.1 months (8.8-34.1). Complete response was observed in 11 patients (19.6%) and partial response in 39 (69.6%), for an ORR of 90.2%, and stable disease in 5 additonal patients (DCR 93.2%), while one patient experienced progressive disease. The median PFS was 25.3 months (95% CI 16.5-34.1) and the median OS was 28.2 months (24.1-32.3). Most TRAEs (85.7%) were grade 1 or 2. Among survivors, 45.5% reported high satisfaction with their QOL, and 84.8% did not experience weight loss. The authors conclude that this combination therapy demonstrated promising efficacy and safety (graphical abstract).