Quantification and statistical analysis
REGRESSION, SECONDARY
All statistical analyses followed the plan specified in the protocol with no deviations and were completed using Stata v17.1 (StataCorp) by independent biostatisticians. Two prespecified interim efficacy analyses were planned Baseline characteristics were compared using t-tests or Mann-Whitney U tests, as appropriate, for continuous and ordinal variables and Fisher’s exact tests for categorical variables. Kaplan-Meier curves were constructed using established methods, and median survival was calculated from these curves. Primary OS and secondary (PFS) HRs were constructed using Cox proportional hazard models with baseline HRs stratified by clinical site. Variance component estimation was performed via bootstrap resampling using 1000 bootstrapped replicates. Specific time-point survival probabilities (6, 9, and 12 months) were calculated using marginal probabilities obtained via logistic regression models, and associated odds ratios were reported. Additionally, an exploratory analysis was performed using a 1- or 1.5-year restricted mean survival time (RMST) to quantify the treatment effects.