According to Simon's optimal two-stage design, 25 patients were required for enrollment to test the null hypothesis that the true ORR is 10% versus the alternative hypothesis that the true ORR is at least 30%, at a significance level of p<0.05 with a power of 80%. If two or more responses were observed among 15 patients in the first stage, the study was continued with 10 additional patients included. As the drop-out rate was assumed to be 10%, the number of patients necessary for recruitment into the study was calculated to be 28.

Descriptive statistics were used to summarize the patients' characteristics, tumor responses, and safety events. The Kaplan-Meier method was used to estimate the median PFS and OS. All enrolled patients were included in an intent-to-treat analysis.