Specific barriers to the conduct of randomized trials.

Large randomized trials are required to provide reliable evidence of the typically moderate benefit of most interventions. To be affordable, such trials need to be simple; to be widely applicable, they need to be close to normal clinical practice. However, current regulations and guidelines have hugely increased trial complexity, effectively becoming barriers to their design and conduct. Key barriers include inadequate funding, overly complex regulations producing needlessly complex trial procedures, excessive monitoring, over restrictive interpretation of privacy laws without evidence of subject benefit, and inadequate understanding of methodology. Complex regulations result in multiple ethics approvals for a multi-center study, unnecessary complexity in the study protocol, delays in securing regulatory approval, and cumbersome regulatory procedures, even for drugs widely used in clinical practice. The type of detailed safety monitoring currently needed in trials of new drugs is being applied indiscriminately to all studies including a simpler and basic level of monitoring that constitutes good practice in most trials could be agreed on, with that level being exceeded only in specific instances. More evidence about the pros and cons of alternative approaches to data quality monitoring would help inform this process. Complex procedures in the form of multiple-page consent forms, overzealous monitoring of side effects and adverse events, source data verification, and over-restrictive approaches to protocol amendments, can impede, rather than facilitate, trial objectives. Finally, further education on the nuances and functions of randomisation would facilitate trial conduct, and reduce the need for burdensome complexity. A radical re-evaluation of existing trial guidelines is needed, based on a clear understanding of the important principles of randomized trials, with the objective of eliminating unnecessary documentation and reporting without sacrificing validity or safety. Researchers should encourage public debate about how best to strike the balance between regulation and cost.

Pharmacokinetic profile of the oral direct thrombin inhibitor dabigatran etexilate in healthy volunteers and patients undergoing total hip replacement.

Dabigatran etexilate is an oral low-molecular-weight direct thrombin inhibitor. Following oral administration, dabigatran etexilate is rapidly converted to its active form, dabigatran. The authors investigated the absorption, distribution, and elimination of a single 150-mg dose capsule formulation of dabigatran etexilate in healthy volunteers and patients undergoing total hip replacement. In an open-label, 3-way crossover study, dabigatran etexilate was administered to 18 male volunteers in the fasted state, after administration of food and with coadministration of the proton pump inhibitor, pantoprazole. In a subsequent multicenter, open-label study, 59 patients received a single dose of dabigatran etexilate, administered 1 to 3 hours following total hip replacement. In healthy volunteers, food had no effect on the extent of absorption of dabigatran etexilate, although there was reduced interindividual variability for dabigatran maximum plasma concentration and AUC(0-infinity). A decrease in the mean dabigatran AUC(0-infinity) (904 to 705 ng*h/mL) occurred with coadministration of pantoprazole. In patients undergoing total hip replacement, immediate onset of absorption was seen with the maximum plasma concentration of dabigatran occurring after 6 hours. The AUC(0-24) of dabigatran was 88% of the steady-state AUC using a preliminary tablet formulation and 106% of that seen in the healthy volunteer study. Compared with healthy volunteers, the postoperative profile was flattened with delayed peak concentrations. In summary, administration of the dabigatran etexilate capsule with food has no effect on the extent of dabigatran absorption, with a moderate decrease when coadministered with pantoprazole. Adequate plasma concentrations of dabigatran were seen with early postoperative administration of the dabigatran etexilate capsule. These pharmacokinetic characteristics confirm the suitability of this oral solid dosage form for use in future clinical trials.