title: Dose finding designs for continuous responses and binary utility.
abstract: Often in clinical trials the observed responses are continuous but a regulatory agency will approve the drug only if the probability is sufficiently large that the efficacy measure exceeds a predefined threshold and the toxicity does not exceed another given threshold. Thus the measure of interest (utility) is based on dichotomized responses. We consider normally distributed correlated responses and build a utility function using the probit transform. Locally optimal designs are used as benchmarks for more practical designs such as composite and adaptive designs. We focus on D-criterion (i.e., all parameters of the dose-response model are of interest) and consider only two-stage designs. It is shown that the practice of reporting dichotomized responses leads to a substantial loss in the precision of estimated parameters (or in the power loss).
authors.affiliation: GlaxoSmithKline, Collegeville, Pennsylvania, USA.
authors.forename: Valerii V
authors.initials: VV
authors.lastname: Fedorov
authors.forename: Yuehui
authors.initials: Y
authors.lastname: Wu
mesh_terms: D002986:Clinical Trials as Topic / Q000379:methods* / Q000706:statistics & numerical data*; D003198:Computer Simulation; D004305:Dose-Response Relationship, Drug; D006801:Humans; D016011:Normal Distribution; D012107:Research Design