Abstract 973P
Background
Programmed cell death protein 1 (PD-1) inhibitors emerged as a promising treatment option for esophageal cancer refractory to standard treatment. PDR001 (spartalizumab) is a humanized IgG4 monoclonal antibody targeting PD-1. We report the results of a single-arm phase II study of PDR001 in the treatment of esophageal squamous cell carcinoma (ESCC) in Korea.
Methods
Inclusion criteria were histologically proven ESCC with a measurable lesion refractory or intolerant to standard therapy. We collected the information regarding patients’ baseline characteristics and responses measured by Response Evaluation Criteria in Solid Tumours version 1.1. The primary endpoint was the overall response rate (ORR). Secondary endpoints included disease control rate (DCR), progression-free survival, overall survival, and duration of response.
Results
Forty-nine patients were screened and a total of 44 eligible patients with ESCC were enrolled. At the data cut-off, the response of 3 patients was pending. The ORR was 18.2% (95% confidence interval [CI], 9.3% to 32.2%), and DCR was 56.8% (95% CI, 42.2% to 70.3%). The most frequent treatment-related adverse events (TRAEs) were grade 1 or 2 hypothyroidism (n = 4) and rash (n = 4). Grade 3 TRAEs included amylase elevation (n = 1), dry mouth (n = 1), sore throat (n = 1), and myalgia (n = 1) but none of them led to treatment delay or discontinuation. No grade 4 or greater TRAEs were reported.
Conclusions
The study is ongoing and PDR001 showed modest clinical benefits with manageable toxicity in refractory ESCC. The efficacy and safety in this population were consistent with those of previous PD-1 inhibitor trials. Biomarker analysis including programmed death ligand 1 (PD-L1) expression are planned.
Clinical trial identification
NCT03785496.
Editorial acknowledgement
The study was supported by K-MASTER project. Novartis provided PDR001.
Legal entity responsible for the study
The authors.
Funding
Novartis.
Disclosure
All authors have declared no conflicts of interest.