Clinical trials crossover design

Crossover design A clinical trial design in which patients receive, in sequence, the treatment (or the control), and then after a specified time, receive the opposite arm of the trial. This allows patients to serve as their own controls. Randomization should be... 

A preliminary assessment of the effect of food on pharmacokinetics can generally be studied in a single-dose, two-arm, randomised, crossover design. Preliminary information can often be obtained by including a fed occasion in the first, dose-escalating study. This will be insuffi-cent for registration purposes, which require an adequately powered study performed with the final formulation, but the information should be sufficient to indicate whether there is need for restrictions on dosing relative to meals in repeat-dose studies in healthy volunteers and patient clinical trials. 

This latter disadvantage led the crossover design to be described as not the design of choice in clinical trials, where unequivocal evidence of treatment effects is required. Over the last 25 years, many statisticians have been more positive about the place of the crossover design in clinical research. ... 

Food and Drug Administration. A report on the two-period crossover design and its applicability in trials of clinical effectiveness. Minutes of... 

The clinical pharmacokinetic-pharmacodynamic study had a double blind, randomized, five-way crossover design, with at least seven days elapsing between trials. Twelve healthy volunteers participated and the treatment conditions were ... 

Elemental considerations may be broad comparisons, such as parallel group versus randomized crossover designs. Simulation also may assist in assigning the trial s primary endpoint, where the simulated probabilities of a successful trial for several clinically meaningful outcomes could be used to determine the most appropriate primary endpoint. 

The TQT study is a randomized, placebo- and positive-controlled clinical trial that can adopt a crossover design or a parallel-group design. The traditional four treatment arms are as follows ... 

We noted previously that both crossover and parallel-gronp designs can be employed in TQT studies. As in any other clinical trial, the issue of statistical power is of interest. When commenting on the topic, Mayo (2009) observed as follows The... 

In double-blind, placebo-controlled clinical trials, bromelain has shown superior results versus placebo in the treatment of sinusitis, inflammation, edema and pain from mediolat-eral episiotomy, postoperative tumiflcations of the feet, arthritis, " and amelioration of ecchymoses and edema in patients with head and face trauma. Oral bioavailability has also been demonstrated (randomized, doubleblind, crossover design trial). ... 

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