Document Detail

Duration of accrual and follow-up for two-stage clinical trials.
MedLine Citation:
PMID:  11280845     Owner:  NLM     Status:  MEDLINE    
Group sequential trials with time to event end points can be complicated to design. Not only are there unlimited choices for the number of events required at each stage, but for each of these choices, there are unlimited combinations of accrual and follow-up at each stage that provide the required events. Methods are presented for determining optimal combinations of accrual and follow-up for two-stage clinical trials with time to event end points. Optimization is based on minimizing the expected total study length as a function of the expected accrual duration or sample size while providing an appropriate overall size and power. Optimal values of expected accrual duration and minimum expected total study length are given assuming an exponential proportional hazards model comparing two treatment groups. The expected total study length can be substantially decreased by including a follow-up period during which accrual is suspended. Conditions that warrant an interim follow-up period are considered, and the gain in efficiency achieved by including an interim follow-up period is quantified. The gain in efficiency should be weighed against the practical difficulties in implementing such designs. An example is given to illustrate the use of these techniques in designing a clinical trial to compare two chemotherapy regimens for lung cancer. Practical considerations of including an interim follow-up period are discussed.
L D Case; T M Morgan
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Publication Detail:
Type:  Journal Article; Research Support, U.S. Gov't, P.H.S.    
Journal Detail:
Title:  Lifetime data analysis     Volume:  7     ISSN:  1380-7870     ISO Abbreviation:  Lifetime Data Anal     Publication Date:  2001 Mar 
Date Detail:
Created Date:  2001-04-02     Completed Date:  2001-04-19     Revised Date:  2007-11-15    
Medline Journal Info:
Nlm Unique ID:  9516348     Medline TA:  Lifetime Data Anal     Country:  United States    
Other Details:
Languages:  eng     Pagination:  21-37     Citation Subset:  IM    
Department of Public Health Sciences and the Comprehensive Cancer Center of Wake Forest University, Wake Forest University School of Medicine, USA.
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MeSH Terms
Antineoplastic Agents / therapeutic use
Carcinoma, Small Cell / drug therapy
Clinical Trials as Topic / methods*
Follow-Up Studies
Lung Neoplasms / drug therapy
Patient Selection
Proportional Hazards Models
Randomized Controlled Trials as Topic / methods
Research Design*
Sample Size
Survival Analysis
Grant Support
5-P30-CA12197/CA/NCI NIH HHS
Reg. No./Substance:
0/Antineoplastic Agents

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine

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