Data analysis and statistical considerations

The primary endpoint was progression-free survival (PFS), and the goal of this study is to show that the addition of autologous CIK cells immunotherapy to a standard TMZ chemoradiotherapy would improve the PFS, as compared with the standard TMZ treatment alone. Secondary end points include overall survival (OS), objective responsive rate (ORR), disease control rate (DCR), Quality of life (QoL), KPS and assessment of adverse effects. PFS was calculated from the date of randomization either until disease progression was confirmed on the MR imaging or death from any causes. OS was calculated from the date of randomization until death from any cause. Objective response rate (OCR) was defined as either a partial or complete response and disease control rate (DCR) as partial, complete response or stable disease.

Sample size for the study was determined on the basis of PFS. Assuming a one-sided type I error of 0.05, a power of 80%, and a randomization ratio for 1:1 between two groups, 86 recurrence or death events were needed to detect a 20% difference (50% vs. 30%) in 12-month PFS. [16] When the potential “loss to follow-up” rate was set at 20%, 180 patients were required to record 86 recurrence or death events. The intention-to-treat (ITT) set was used to evaluate efficacy and included all randomized patients. The patients who completed treatment as planned were included in the per protocol set (PP set). Therapeutic outcomes were assessed based on the ITT set. Kaplan-Meier curves were generated for PFS and OS, and the log-rank test was used for group comparisons. A Cox's proportional hazard analysis was done to assess the treatment effect after adjustment for baseline characteristics.

Adverse events were compared between two groups by chi-square or Fisher's exact test. The log-rank test for the primary endpoint was one-sided, and all other statistical tests were two-sided. Statistical significance was set at P < .05. Statistical analysis was performed by statistician in the Department of Statistics at Korea university (Seoul, Korea) using SAS software version 9.2 (SAS Institute Inc., Cary, NC, USA).