The innovative doubly randomized delayed start(DRDS)design has been implemented to tackle the well-known challenge of a high placebo response rate in clinical trials.This design begins with a conventional parallel des...The innovative doubly randomized delayed start(DRDS)design has been implemented to tackle the well-known challenge of a high placebo response rate in clinical trials.This design begins with a conventional parallel design phase(period 1),followed by a subsequent phase(period 2)where subjects initially assigned to placebo and who did not respond are re-randomized to either the test drug or placebo.Chi,G.Y.,Li,Y.,Liu,Y.,Lewin,D.,&Lim,P.(2016 On clinical trials with a high placebo response rate.Contemporary Clinical Trials Communications,2,34-53.https:/doi.org/10.1016/j.conctc.2015.10.002)introduced a new statistical methodology with a conditional probability structure to account for the specific characteristics of the DRDS design.However,some critical formulas in Chi et al.(2016,p.38)for this probability structure are incorrect.Here,we correct these formulas and provide a comprehensive technical background on deriving the probability structurefor a DRDS design to support these corrections.展开更多
文摘The innovative doubly randomized delayed start(DRDS)design has been implemented to tackle the well-known challenge of a high placebo response rate in clinical trials.This design begins with a conventional parallel design phase(period 1),followed by a subsequent phase(period 2)where subjects initially assigned to placebo and who did not respond are re-randomized to either the test drug or placebo.Chi,G.Y.,Li,Y.,Liu,Y.,Lewin,D.,&Lim,P.(2016 On clinical trials with a high placebo response rate.Contemporary Clinical Trials Communications,2,34-53.https:/doi.org/10.1016/j.conctc.2015.10.002)introduced a new statistical methodology with a conditional probability structure to account for the specific characteristics of the DRDS design.However,some critical formulas in Chi et al.(2016,p.38)for this probability structure are incorrect.Here,we correct these formulas and provide a comprehensive technical background on deriving the probability structurefor a DRDS design to support these corrections.
