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Generalizing boundaries for triangular designs, and efficacy estimation at extended follow-ups

Overview of attention for article published in Trials, November 2015
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Title
Generalizing boundaries for triangular designs, and efficacy estimation at extended follow-ups
Published in
Trials, November 2015
DOI 10.1186/s13063-015-1018-1
Pubmed ID
Authors

Annabel Allison, Tansy Edwards, Raymond Omollo, Fabiana Alves, Dominic Magirr, Neal D. E. Alexander

Abstract

Visceral leishmaniasis (VL) is a parasitic disease transmitted by sandflies and is fatal if left untreated. Phase II trials of new treatment regimens for VL are primarily carried out to evaluate safety and efficacy, while pharmacokinetic data are also important to inform future combination treatment regimens. The efficacy of VL treatments is evaluated at two time points, initial cure, when treatment is completed and definitive cure, commonly 6 months post end of treatment, to allow for slow response to treatment and detection of relapses. This paper investigates a generalization of the triangular design to impose a minimum sample size for pharmacokinetic or other analyses, and methods to estimate efficacy at extended follow-up accounting for the sequential design and changes in cure status during extended follow-up. We provided R functions that generalize the triangular design to impose a minimum sample size before allowing stopping for efficacy. For estimation of efficacy at a second, extended, follow-up time, the performance of a shrinkage estimator (SHE), a probability tree estimator (PTE) and the maximum likelihood estimator (MLE) for estimation was assessed by simulation. The SHE and PTE are viable approaches to estimate an extended follow-up although the SHE performed better than the PTE: the bias and root mean square error were lower and coverage probabilities higher. Generalization of the triangular design is simple to implement for adaptations to meet requirements for pharmacokinetic analyses. Using the simple MLE approach to estimate efficacy at extended follow-up will lead to biased results, generally over-estimating treatment success. The SHE is recommended in trials of two or more treatments. The PTE is an acceptable alternative for one-arm trials or where use of the SHE is not possible due to computational complexity. NCT01067443 , February 2010.

Twitter Demographics

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Mendeley readers

The data shown below were compiled from readership statistics for 21 Mendeley readers of this research output. Click here to see the associated Mendeley record.

Geographical breakdown

Country Count As %
Unknown 21 100%

Demographic breakdown

Readers by professional status Count As %
Researcher 4 19%
Student > Master 4 19%
Student > Ph. D. Student 4 19%
Student > Bachelor 2 10%
Other 2 10%
Other 1 5%
Unknown 4 19%
Readers by discipline Count As %
Medicine and Dentistry 6 29%
Nursing and Health Professions 2 10%
Business, Management and Accounting 2 10%
Agricultural and Biological Sciences 1 5%
Mathematics 1 5%
Other 2 10%
Unknown 7 33%

Attention Score in Context

This research output has an Altmetric Attention Score of 1. This is our high-level measure of the quality and quantity of online attention that it has received. This Attention Score, as well as the ranking and number of research outputs shown below, was calculated when the research output was last mentioned on 20 November 2015.
All research outputs
#4,874,083
of 6,588,247 outputs
Outputs from Trials
#1,508
of 1,934 outputs
Outputs of similar age
#168,832
of 248,371 outputs
Outputs of similar age from Trials
#104
of 151 outputs
Altmetric has tracked 6,588,247 research outputs across all sources so far. This one is in the 14th percentile – i.e., 14% of other outputs scored the same or lower than it.
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