Lactate dehydrogenase and baseline markers associated with clinical outcomes of advanced esophageal squamous cell carcinoma patients treated with camrelizumab (SHR-1210), a novel anti-PD-1 antibody

Background A small proportion of patients with advanced esophageal squamous cell carcinoma (ESCC) could benefit from immune checkpoint inhibitors; however, reliable peripheral blood biomarkers for outcomes of anti-PD-1 immunotherapy in ESCC have not been identified. Methods The data of 43 patients in the ESCC cohort of a phase I trial at our center were retrospectively reviewed. All patients were administered intravenous camrelizumab (SHR-1210), a novel anti-PD-1 antibody, at doses of 60 mg, 200 mg, or 400 mg (4-week interval after first dose followed by a 2-week schedule) until disease progression or intolerable toxicity. Associations between lactate dehydrogenase (LDH) and other peripheral blood biomarkers at baseline and the efficacy of camrelizumab were also investigated. Results After median follow-up of 19.6 months, the overall response rate was 25.6% (11/43), including one complete response. Median progression-free and overall survival rates were 2.0 and 8.0 months, respectively. Patients with an elevated baseline LDH had lower tumor response rates (P = 0.02) and shorter progression-free (P = 0.002) and overall (P < 0.0001) survival than patients with normal LDH levels. An increase in LDH levels during treatment was significantly associated with disease progression. Multivariate Cox analysis identified LDH (hazard ratio [HR] 0.18), CRP (HR 0.27), the number of organs involved (HR 0.31), absolute monocyte count (HR 0.33), and Eastern Cooperative Oncology Group performance status (HR 0.36) as independent prognostic factors. Conclusions Serum LDH, which is readily available in routine clinical practice, is a potential marker for response and a powerful independent factor for survival in advanced ESCC patients treated with anti-PD-1 therapy.