[in Japanese]

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In Japan, more than 1000 institutional review boards (IRBs) were registered with the Pharmaceuticals and Medical Devices Agency (PMDA) as of April 2012. To improve efficiency, the Ministry of Health, Labour and Welfare calls for active utilization of cooperative or central IRBs. However, little progress has been made. The sponsors address this issue from the point of view of efficiency. Therefore, we performed a nationwide questionnaire survey on the status of IRB. Many medical institutions individually established IRBs, but the secretariats of IRBs felt that the duties were a burden. On the other hand, there was reluctance to request review from other IRBs. Such situation is similar to that in the Netherlands before accreditation was introduced. As the installation standard of IRB was set up by the government, an accreditation system should also be set up by the government or an independent agency and aggregation of local IRBs to one that meets the accreditation standard would be required to improve efficiency and quality of review on clinical trials.

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Background: Non-vitamin K antagonist oral anticoagulants (NOACs) show a favorable balance between efficacy and safety compared to warfarin in patients with non-valvular atrial fibrillation (NVAF). NOACs are mainly or partially eliminated by the kidneys. The aim of this study was to evaluate the influence of renal function on treatment persistence with NOACs and to compare NOAC and warfarin treatments in Japanese NVAF patients.
Methods: We retrospectively studied 819 NVAF patients who newly started NOACs during the first 24 months after our hospital adopted the use of these drugs (249 patients treated with dabigatran, 156 with rivaroxaban, and 202 with apixaban) and 212 NVAF patients who newly started warfarin during the same period. Impaired renal function was defined as a decrease in creatinine clearance (CrCl) to below 50 mL/min. The endpoint was discontinuation of each drug.
Results: During the follow-up period, 139 (23%) patients who newly started NOACs and 22 (10%) patients who newly started warfarin discontinued the drug. The patients who were prescribed NOACs were less likely to continue treatment than those who were prescribed warfarin. Among patients with CrCl < 50 mL/min, those who were prescribed NOACs had lower 12-month persistence rates (dabigatran, 47.4%; rivaroxaban 63.2%; apixaban, 80.6%; and warfarin, 98.2%) than those who were prescribed warfarin. The most common reason for discontinuation was the occurrence of adverse events including gastrointestinal symptoms and bleeding.
Conclusions: Our study showed a significantly lower persistent rate in NVAF patients who were prescribed NOACs compared to patients who were prescribed warfarin, especially among the patients with CrCl below 50 mL/min.

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