Abstract
Since the introduction of the Orphan Drug Development Support Program in 1993 in Japan, the MHW has designated 106 orphan drugs (additional 7 designations were granted but those applications were made by the request of the MHW). Among 106 drugs, 34 were approved by the Pharmaceutical Affairs Law.
The designations represent 90 compounds in which 32 biologicals were involved; 11 compounds received the designation more than once. Among 90 compounds, 54 were newly developed. The applications for orphan drug designation were made by 70 different sponsors. Of the orphan drug designations 23 were those for infections including AIDS or infectious conditions, 13 each for cancer and nerve disorders and 9 for blood disorders. Twenty-five compounds were for 15 indications classified as “nanbyou” or “recalcitrant illness”. In the 91.9% of the designated orphan drugs the number of patients for whom the designated drug will be used is estimated to be not more than 10, 000. Among 106 designations, 36 were Japanese original products. However only 9 designations contain new compounds.
Of the designated drugs 33.7% have obtained approval and 4.7% of the designations have been withdrawn. On the other hand, in USA, 19.2% have been approved and 15.5% have been withdrawn. Only a few compounds have been designated repeatedly in Japan.
Thus there is the tendency that the orphan drugs which need less development expenditure and shorter development time are selected. Such a trend can be explained by the fact that almost all orphan drugs have been developed by big companies in Japan rather than by venture companies as in USA.
