Randomisation dynamic

Dynamic randomisation - minimisation When there are a large number of prognostic variables to account for, it may be practically difficult to implement a fully stratified randomisation scheme. The reason being that with a large number of factors there are even more individual stratum combinations and therefore there will be very few patients in many of the combinations. In such circumstances the method of dynamic allocation, or minimisation, has been recommended. 

Dynamic aibcation is an alternative procedure in which the allocation of treatment to a subject is influenced by the current balance of allocated treatments and, in a stratified trial, by the stratum to which the subject belongs and the balance within that stratum. Deterministic dynamic allocation procedures should be avoided and an appropriate element of randomisation should be incorporated for each treatment allocation. ... 

Dynamic allocation moves away from having a pre-specified randomisation list and the allocation of patients evolves as the trial proceeds. The method looks at the current balance, in terms of the mix of patients and a number of pre-specified factors, and allocates the next patient in an optimum way to help redress any imbalances that exist at that time. 

So if you are planning a trial then stick with stratification and avoid dynamic allocation. If you have an ongoing trial which is using dynamic allocation then continue, but be prepared at the statistical analysis stage to supplement the standard methods of calculating p-values with more complex methods which take account of the dynamic allocation scheme. These methods go under the name of randomisation tests. 

Other problems pointed out by Box et al. [20] are serially correlated errors, dynamic relations and feedback. All the above problems can be overcome by the use of properly designed statistical experiments that employ features such as randomisation, blocking and other suitable controls. 

As the olefin becomes more complex, more reaction pathways and products become possible and the dynamics are even more complicated. In the case of the reaction of F with various butenes [585, 587], both CH3 and H substitution pathways can occur via long-lived collision complexes. The relative cross sections for the two different channels agree with RRKM predictions in most cases, indicating energy randomisation and some... 

Gappa M, Gartner M, Poets CF, von der Haidt H. Effects of salbutamol delivery from a metered dose inhaler versus jet nebulizer on dynamic Itmg mechanics in very preterm infants with chronic Itmg disease. Pediatr Pnlmonol 1997 23 442-448. Yuksel B, Gteenough A. Randomised trial of inhaled steroids in preterm infants with respiratory symptoms at follow up. Thorax 1992 47 910-913. 

Examination of the nature of randomisation processes is still in its infancy, both on the experimental and theoretical fronts. The most straightforward experimental approach has been that of the formation of highly energetic symmetric molecules from unsymmetric precursors, followed by the observation of an asymmetric formation of products [71.R2 81.L]. Next, we have many examples nowadays, e.g. [81.L 82.S4], where non-statistical energy distributions are observed either in or between the products formed in unimolecular fragmentation reactions these observations contain information about the degree of randomisation in the reactant molecule, but the deconvolution of such experimental data to obtain that information is likely to be a formidable task [81.P2]. Finally, we have a rapidly growing array of laser-based experiments which probe the dynamics of the molecular motions subsequent to the initial excitation, see e.g. [81J]. 

EribuUn Eribulin mesylate is a nontaxane microtubule dynamics inhibitor that is currently under development in phase I-III trials for the treatment of solid tumours. The effects of ketoconazole on eribulin pharmacokinetics were evaluated in a randomised crossover study in 12 patients [52f. Ketoconazole had no effect on eribulin pharmacokinetics and suggest that cytochrome P450 3A inhibitors do not interfere eribulin metabolism. 

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