Search

Your search keyword '"Dragalin, Vlad"' showing total 4 results
Start Over Author "Dragalin, Vlad"
4 results on '"Dragalin, Vlad"'

3. A bivariate Bayesian dose-finding procedure applied to a seamless phase I/II trial in rheumatoid arthritis

Author

Thygesen, Helene, Dragalin, Vlad, Whitehead, Anne, Whitehead, John, Thygesen, Helene, Dragalin, Vlad, Whitehead, Anne, and Whitehead, John

Abstract

We describe a dose escalation procedure for a combined phase I/II clinical trial. The procedure is based on a Bayesian model for the joint distribution of the occurrence of a dose limiting event and of some indicator of efficacy (both considered binary variables) making no assumptions other than monotonicity. Thus the chances of each outcome are assumed to be nondecreasing in dose level. We applied the procedure to the design of a placebo-controlled, sequential trial in rheumatoid arthritis, in each stage of which patients were randomized between placebo and all dose levels that currently appeared safe and non-futile. Based on data from a pilot study, we constructed five different scenarios for the dose-response relationships under which we simulated the trial and assessed the performance of the procedure. The new design appears to have satisfactory operating characteristics, and can be adapted to the requirements of a range of trial situations.

Published
2012

4. Designing Issues in Confirmatory Adaptive Population Enrichment Trials.

Author

Wassmer, Gernot and Dragalin, Vlad

Subjects
*SOCIAL status, *GENDER, *ECONOMICS, *SOCIOLOGY, *FOSTER home care
Abstract

Adaptive population enrichment designs enable the data-driven selection of one or more pre-specified subpopulations in an interim analysis, and the confirmatory proof of efficacy in the selected subset at the end of the trial. Sample size reassessment and other adaptive design changes can be performed as well. Strong control of the experimentwise Type I error rate is guaranteed by use of the combination testing principle together with the closed testing argument. In this paper the general methodology and designing issues when planning such a design are reviewed. It is shown how to derive overall confidence intervals andp-values. Criteria for assessing the operating characteristics of these designs are given, and the application is illustrated by examples. [ABSTRACT FROM AUTHOR]

Published
2015
Full Text
View/download PDF

Catalog

Books, media, physical & digital resources
See catalog results