紀要論文

後発医薬品の市場シェア決定要因と普及促進政策の効果 : 高脂血症薬「プラバスタチン」における後発医薬品参入の事例

What Explains the Market Share of Generic Drugs in Japan? The Effect of a Policy Promoting Generics on the Innovative Branded Product and Its Generics within　the "Pravastatin" Market

jpn

00229741

https://doi.org/10.15002/00009659

法政大学経済学部学会

81

2・3・4

83

108

2014-03-31

Version of Record

小椋正立教授退職記念号

This article examines the factors that determine the share of generic drugs in Japan’s pharmaceutical market. Under strong pressure to limit the cost of Japan' s national health care system, the government, in recent years, has introduced several policies to promote the use of generic drugs. Actually, the market share of generic drugs might be determined not only by the effect of such policies but also by the price gap that exists when these drugs are compared to brand name drugs, the good-will shown to a product, the amount of growth in the market for any particular therapeutic class, and so on. First, we outline our theoretical framework regarding the determinants of market share based on the relationships between branded products and generics, and estimate the determinant function of the generics’ share by using trading data covering all Japan from 2001 to 2013. Focusing on the area of hyperlipidemia, we investigate the share of generics within the "pravastatin" market, which has been dominated by the innovative brand name drug "mebarotin". Overall, our results suggest that the government policy promoting generics has had a strong positive effect on expanding generics' market share as has the difference in price between the generics and the branded product, but it is not observed that any good-will towards generics that has been generated from a growing amount of medical advertisements has had any significant effect on the generics' market share.

Article

AN00071028