Statistical analysis
Based on the study design, the patients were separated into arms A and B according to PD-L1 expression. Assuming an MPR rate of 35%, based on the literature and a 5% dropout rate, a sample size of 24 patients at least in each arm was employed to obtain 80% power with a type I error of 0.025.The efficacy and safety analyses set were evaluated in all enrolled patients, and the 95% confidence interval (CI) for response rates were calculated utilizing the exact binomial distribution. Qualitative variables are presented as the absolute and relative frequency, and quantitative variables are presented as the median (IQR) or mean (SD).Associations between qualitative variables were tested through the Cochran–Armitage and Fisher’s exact tests. Survival curves were generated through Kaplan–Meier analysis and compared through the log-rank tests. Hazard ratios (HR) and the associated 95% CIs were calculated based on the Cox proportional hazard models. All statistical analyses were carried out utilizing R statistical software (version 3.6.2).