Aiyi Liu1, Chunling Liu, Qizhai Li, Kai F Yu, Vivian W Yuan. 1. Biostatistics and Bioinformatics Branch, Eunice Kennedy Shriver National Institute of Child Health and Human Development, Rockville, MD 20852, USA. liua@mail.nih.gov
Abstract
BACKGROUND: Large comparative clinical trials usually target a wide-range of patients population in which subgroups exist according to certain patients' characteristics. Often, scientific knowledge or existing empirical data support the assumption that patients' improvement is larger among certain subgroups than others. Such information can be used to design a more cost-effective clinical trial. PURPOSE: The goal of the article is to use such information to design a more cost-effective clinical trial. METHODS: A two-stage sample-enrichment design strategy is proposed that begins with enrollment from certain subgroup of patients and allows the trial to be terminated for futility in that subgroup. RESULTS: Simulation studies show that the two-stage sample-enrichment strategy is cost-effective if indeed the null hypothesis of no treatment improvement is true, as also so illustrated with data from a completed trial of calcium to prevent preeclampsia. LIMITATIONS: Feasibility of the proposed enrichment design relies on the knowledge prior to the start of the trial that certain patients can benefit more than others from the treatment. Prolonged accrual and longer-waited outcomes may hinder utilization of the proposed design. CONCLUSIONS: The two-stage sample-enrichment approach borrows strength from treatment heterogeneity among target patients in a large-scale comparative clinical trial, and is more cost-effective if the treatment arms are indeed of no difference.
BACKGROUND: Large comparative clinical trials usually target a wide-range of patients population in which subgroups exist according to certain patients' characteristics. Often, scientific knowledge or existing empirical data support the assumption that patients' improvement is larger among certain subgroups than others. Such information can be used to design a more cost-effective clinical trial. PURPOSE: The goal of the article is to use such information to design a more cost-effective clinical trial. METHODS: A two-stage sample-enrichment design strategy is proposed that begins with enrollment from certain subgroup of patients and allows the trial to be terminated for futility in that subgroup. RESULTS: Simulation studies show that the two-stage sample-enrichment strategy is cost-effective if indeed the null hypothesis of no treatment improvement is true, as also so illustrated with data from a completed trial of calcium to prevent preeclampsia. LIMITATIONS: Feasibility of the proposed enrichment design relies on the knowledge prior to the start of the trial that certain patients can benefit more than others from the treatment. Prolonged accrual and longer-waited outcomes may hinder utilization of the proposed design. CONCLUSIONS: The two-stage sample-enrichment approach borrows strength from treatment heterogeneity among target patients in a large-scale comparative clinical trial, and is more cost-effective if the treatment arms are indeed of no difference.
Authors: R J Levine; J R Esterlitz; E G Raymond; R DerSimonian; J C Hauth; L Ben Curet; B M Sibai; P M Catalano; C D Morris; J D Clemens; M G Ewell; S A Friedman; R L Goldenberg; S L Jacobson; G M Joffe; M A Klebanoff; A S Petrulis; J G Rigau-Perez Journal: Control Clin Trials Date: 1996-10
Authors: R J Levine; J C Hauth; L B Curet; B M Sibai; P M Catalano; C D Morris; R DerSimonian; J R Esterlitz; E G Raymond; D E Bild; J D Clemens; J A Cutler Journal: N Engl J Med Date: 1997-07-10 Impact factor: 91.245
Authors: W C Cushman; J A Cutler; S F Bingham; T Harford; E Hanna; P Dubbert; J F Collins; M Dufour; D Follman; P S Allender Journal: Am J Hypertens Date: 1994-09 Impact factor: 2.689