title: Adaptive design: estimation and inference with censored data in a semiparametric model.
abstract: In this article, we provide a method of estimation for the treatment effect in the adaptive design for censored survival data with or without adjusting for risk factors other than the treatment indicator. Within the semiparametric Cox proportional hazards model, we propose a bias-adjusted parameter estimator for the treatment coefficient and its asymptotic confidence interval at the end of the trial. The method for obtaining an asymptotic confidence interval and point estimator is based on a general distribution property of the final test statistic from the weighted linear rank statistics at the interims with or without considering the nuisance covariates. The computation of the estimates is straightforward. Extensive simulation studies show that the asymptotic confidence intervals have reasonable nominal probability of coverage, and the proposed point estimators are nearly unbiased with practical sample sizes.
authors.affiliation: Department of Biostatistics, M D Anderson Cancer Center, Houston, TX 77030, USA. yshen@mdanderson.org
authors.forename: Yu
authors.initials: Y
authors.lastname: Shen
authors.forename: Yi
authors.initials: Y
authors.lastname: Cheng
mesh_terms: D000971:Antineoplastic Combined Chemotherapy Protocols / Q000627:therapeutic use; D015179:Colorectal Neoplasms / Q000188:drug therapy; D003198:Computer Simulation; D016001:Confidence Intervals; D003627:Data Interpretation, Statistical; D005472:Fluorouracil / Q000008:administration & dosage; D007978:Levamisole / Q000008:administration & dosage / Q000627:therapeutic use; D009364:Neoplasm Recurrence, Local / Q000517:prevention & control; D016016:Proportional Hazards Models; D016032:Randomized Controlled Trials as Topic / Q000379:methods*; D012107:Research Design; D016896:Treatment Outcome
chemical_list: D007978:Levamisole; D005472:Fluorouracil