A five-year analysis of market share and sales growth for original drugs after patent expiration in Korea

Abstract Introduction: The sales patterns of original drugs after patent expiration in Korea differ from those in other countries. This study investigates how they differ. Methods: Using data from the Ministry of Food and Drug Safety, original drugs whose patents expired in 2012–2018 were divided into two groups depending on the generic drug approval. The differences in the attributes of each variable were analyzed. Additionally, we used IQVIA data to determine the market share and growth rate of 48 original drugs over five years from the launch of the first generic drug. Results: The average sales before the patent expiration of original drugs without a generic drug and the average sales before the first generic drug launch of original drugs with generic drugs were KRW 2.9 and 22.6 billion, respectively. The sales volume of off-patent original drugs in the fifth year had an average growth rate of 150.6% compared with that before the first generic drug launch, indicating a different trend from other countries. The average market share of off-patent original drugs in the same molecule market in the fifth year was 70.6%, which was higher than previously reported research results in Korea and other countries. Conclusion: This study analyzed the trend of original drugs’ sales volume, value, growth, and market share after the launch of a first generic drug. Furthermore, it demonstrated different patterns from those of other countries.