Critical review of 'Public domain application': a flexible drug approval system in Japan

'Public domain application' is a flexible drug approval system in Japan, similar to the fast track designation in the United States.

From 1999 to 2009, four drugs and three regimens received approval from `Public domain application'. The data from the review reports were extracted, and the reviewing process was critically re-evaluated.

The study drugs were categorized into three groups according to the sizes of the studies and evidence levels in the original articles that were submitted. Carboplatin was categorized into the first group with a large number of study patients and a high evidence level; the review report had studies with more than 15 000 total patients and 8 phase III studies. The ifosfamide and vinblastine regimen was categorized into the second group, with a low number of study patients and a low evidence level; the review report had studies with less than 1000 total patients and 1 phase III study. Dacarbazine; cytarabine; methotrexate, vinblastine, doxorubicin, and cisplatin; bleomycin, etoposide, and cisplatin; and fludarabine were categorized into the remaining third group, with a moderate number of study patients and evidence level.

Drugs with various backgrounds, including evidence levels and physicians' experiences, were approved via `Public domain application'. The approvals of most drugs were evaluated to be appropriate.