Sequential allocation in clinical trials comparing two exponential survival curves

Research output: Contribution to journalArticle

Abstract

The problem of comparing two medical treatments with respect to survival is considered. Treatment outcome is assumed to follow an exponential distribution. The ratio of expected survivals associated with the two treatments is the clinical parameter of interest. A nuisance parameter is present, but it is removed by an invariance reduction and a sequential probability ratio test is applied to the invariant likelihood ratio. A class of data-dependent treatment assignment rules is identified over which the probability of correct treatment selection at the termination of the trial is approximately constant. A cost function, the weighted sum of total patients in the trial and the number assigned to the inferior treatment is introduced and a treatment allocation rule conjectured to minimize the expected cost is constructed. Both analytic and simulation results show that it is an improvement over rules previously proposed. The methodology contained herein can be used to construct near-optimal rules in other testing contexts.

Original languageEnglish (US)
Pages (from-to)627-634
Number of pages8
JournalBiometrics
Volume33
Issue number4
StatePublished - 1977
Externally publishedYes

Fingerprint

Clinical Trials
clinical trials
Curve
Survival
medical treatment
Invariance
Cost functions
testing
Testing
Therapeutics
Costs
Costs and Cost Analysis
Sequential Probability Ratio Test
Nuisance Parameter
Dependent Data
Likelihood Ratio
Weighted Sums
Exponential distribution
Termination
Cost Function

ASJC Scopus subject areas

  • Agricultural and Biological Sciences(all)
  • Agricultural and Biological Sciences (miscellaneous)
  • Applied Mathematics
  • Statistics and Probability
  • Public Health, Environmental and Occupational Health

Cite this

Sequential allocation in clinical trials comparing two exponential survival curves. / Louis, Thomas.

In: Biometrics, Vol. 33, No. 4, 1977, p. 627-634.

Research output: Contribution to journalArticle

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