21 papers · ranked by Valyu relevance
Ruyi Liu, Fan Li, Denise Esserman, Mary Ryan
The two-stage preference design (TSPD) enables the inference for treatment efficacy while allowing for incorporation of patient preference to treatment. It can provide unbiased estimates for selection and preference effects, where a selection effect occurs when patients who prefer one treatment respond differently than…
Stephen Schüürhuis, Gernot Wassmer, Meinhard Kieser, Friedrich Pahlke + 2 more
Background In group-sequential designs, it is typically assumed that there is no time gap between patient enrollment and outcome measurement in clinical trials. However, in practice, there is usually a lag between the two time points. This can affect the statistical analysis of the data, especially in trials with…
Zhangyi He, Suzie Cro, Laurent Billot
Group sequential designs (GSDs) are well established and the most commonly used adaptive design in confirmatory clinical trials with interim analyses. However, they remain underutilised, and their implementation involves unique theoretical and practical decisions that demand careful consideration to optimise…
Konrad Neumann, Ulrike Grittner, Sophie K. Piper, Andre Rex + 8 more
'Oscar Florez-Vargas' 'George Karystianis' 'Alice Schneider' 'Ian Wellwood' 'Bob Siegerink' 'John P. A. Ioannidis' 'Jonathan Kimmelman' 'Ulrich Dirnagl'] Despite the potential benefits of sequential designs, studies evaluating treatments or experimental manipulations in preclinical experimental biomedicine almost…
Michael J. Grayling, James M. S. Wason, Adrian P. Mander
We describe and compare two methods for the group sequential design of two-arm experiments with Poisson distributed data, which are based on a normal approximation and exact calculations respectively. A framework to determine near-optimal stopping boundaries is also presented. Using this framework, for a considered…
Long-Hao Xu, Tobias Mütze, Frank Konietschke, Tim Friede
In group sequential designs, where several data looks are conducted for early stopping, we generally assume the vector of test statistics from the sequential analyses follows (at least approximately or asymptotially) a multivariate normal distribution. However, it is well-known that test statistics for which an…
Fraser Lewis
A group sequential clinical trial design can be an attractive option when planning a pivotal trial as this approach has the ability to stop the trial early for success, whilst also being well accepted from a regulatory review perspective. Compared to a single stage design there are more moving parts to consider and…
Guanhong Miao, Jason J. Z. Liao, Jing Yang, Keaven Anderson
Background Due to the high cost and high failure rate of Phase III trials where a classical group sequential design (GSD) is usually used, seamless Phase II/III designs are more and more popular to improve trial efficiency. A potential attraction of Phase II/III design is to allow a randomized proof-of-concept stage…
Sonja Zehetmayer, Martin Posch, Franz Koenig
When testing multiple hypotheses, a suitable error rate should be controlled even in exploratory trials. Conventional methods to control the False Discovery Rate assume that all p-values are available at the time point of test decision. In platform trials, however, treatment arms enter and leave the trial at different…
Sergey Tarima, Nancy Flournoy
This manuscript investigates unconditional and conditional-on-stopping maximum likelihood estimators (MLEs), information measures and information loss associated with conditioning in group sequential designs (GSDs). The possibility of early stopping brings truncation to the distributional form of MLEs; sequentially…
Michael J. Grayling, James M. S. Wason, Adrian P. Mander
familywise error rate M. J. Grayling et al. Authors: ['Michael J. Grayling' 'James M. S. Wason' 'Adrian P. Mander'] Title: Abstract Crossover designs are an extremely useful tool to investigators, and group sequential methods have proven highly proficient at improving the efficiency of parallel group trials. Yet, group…
Tobias Mütze, Ekkehard Glimm, Heinz Schmidli, Tim Friede
Count data and recurrent events in clinical trials, such as the number of lesions in magnetic resonance imaging in multiple sclerosis, the number of relapses in multiple sclerosis, the number of hospitalizations in heart failure, and the number of exacerbations in asthma or in chronic obstructive pulmonary disease…
John P. Veillette, Letitia Ho, Howard C. Nusbaum
Cognitive neuroscientists have been grappling with two related experimental design problems. First, the complexity of neuroimaging data (e.g. often hundreds of thousands of correlated measurements) and analysis pipelines demands bespoke, non-parametric statistical tests for valid inference, and these tests often lack…
Qi Zhang, Chang Liu, Stephen Wu, Ryo Yoshida
In the last few years, de novo molecular design using machine learning has made great technical progress but its practical deployment has not been as successful. This is mostly owing to the cost and technical difficulty of synthesizing such computationally designed molecules. To overcome such barriers, various methods…
Authors not listed
Incorporating non-natural amino acids (NNAAs) into peptides enhances therapeutic properties, including binding affinity, metabolic stability, and in vivo half-life time. The pursuit of novel NNAAs for improved peptide designs faces the challenge of effective synthesis. Solid-Phase Peptide Synthesis (SPPS) is an…
Helena Wright-Wieckowski, Kate Wilmut, Katja Kornysheva
Research suggests that motor difficulties in Developmental Coordination Disorder (DCD) are related to altered motor sequence planning, but it is unclear which mechanisms are affected, particularly in adults. This study addresses that gap by examining how the order of upcoming movements during the planning of skilled…
Helena Wright-Wieckowski, Jason Friedman, Joseph M. Galea, Katja Kornysheva
Results in human and non-human primates have shown that elements of a movement sequence are pre-ordered in parallel competitively before execution, a process known as competitive queueing (CQ). However, it is unclear whether the preplanning of individual movements persists in continuous skilled actions that involve…
Juliana E. Trach, Theresa H. McKim, Theresa M. Desrochers
Everyday task sequences, such as cooking, contain overarching goals (completing the meal), sub-goals (prepare vegetables), and motor actions (chopping). Such tasks generally are considered hierarchical because superordinate levels (e.g., goals) affect performance at subordinate levels (e.g., sub-goals and motor…
Simor Peter, Zavecz Zsofia, Horváth Kata, Éltető Noémi + 4 more
Procedural learning is a fundamental cognitive function that facilitates efficient processing of and automatic responses to complex environmental stimuli. Here, we examined training-dependent and off-line changes of two sub-processes of procedural learning: namely, sequence learning and statistical learning. Whereas…
Kristy V. Dang, Darius E. Parvin, Richard B. Ivry
The classic advice given to anyone learning a new skill is “practice makes perfect.” While this provides a good general rule to follow, it lacks any detail on what form of practice will efficiently maximize learning. So when faced with the task of acquiring multiple skills, what is the optimal way to learn? Would it be…
Babu Bassa
In this communication the author describes a software tool named "ChameleonSort". The software program, developed by the present author is useful in the sorting of biological sequence variants like those accumulating mutations while diverging from the common ancestors. Examples include viral protein variants, protein…