1262TiP Efficacy and safety of consolidative camrelizumab following definitive concurrent chemoradiotherapy in patients with locally advanced esophageal squamous cell cancer

Definitive concurrent chemoradiotherapy (CCRT) has become the standard of care in patients (pts) with unresectable locally advanced esophageal squamous cell carcinoma (ESCC). However, some patients still experience local failure or distant metastasis. The PACIFIC study has confirmed that consolidation immunotherapy with durvalumab significantly improves the progression-free survival (PFS) and overall survival (OS) for patients with unresectable, stage III non small cell lung cancer (NSCLC) after CCRT, but the efficacy of consolidation immunotherapy for unresectable esophageal cancer is unclear. We performed a clinical trial to investigate the clinical efficacy of camrelizumab (an anti-PD-1 monoclonal antibody) on pts with unresectable locally advanced ESCC after definitive CCRT. We prospectively enrolled unresectable locally advanced ESCC patients. Camrelizumab was intravenously administered over 30 min at a dose of 200 mg on day 1 every two weeks. Key eligibility criteria were as follows: 18-75 years old, stage of Ⅱ-Ⅳa (T1bN+M0, T2-4N0-2M0), complete of definitive concurrent chemoradiotherapy (50-60Gy with involved-field irradiation). The primary end point was PFS. The secondary end points included OS and safety.From April 2020 to March 2022, the interim analysis included 12 patients. 11 pts had stable disease, and 1 patient had progressive disease. The median follow-up was 15 months. Median PFS and OS were not reached. The mean lung dose (MLD) and V20 of total lung was 1172.8Gy (range:838.2-1448.4Gy) and 23% (range:16-29%), respectively. The most common adverse events of grade 1 or 2 included reactive cutaneous capillary endothelial proliferation (8, 61%), pneumonitis (4, 31%)，hypothyroidism (2,15%), hyperthyroidism (1, 8%), transfusion reaction(1, 8%) and no grade 3 or 4 adverse events occurred.The interim results suggested that consolidative camrelizumab following definitive concurrent chemoradiotherapy might have a promising efficacy and manageable toxicities in patients with unresectable locally advanced ESCC. This trial is still ongoing and the final analysis will be conducted after study completion. NCT04286958. The authors. Has not received any funding.