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 show a relatively high market share and continuous sales growth differently from those in the U.S. and European countries. This study aims to investigates a five-year sales pattern of original drugs after patent expiration in Korea using empirical data. Methods: Using data from the Ministry of Food and Drug Safety, original drugs whose patents expired in 2012–2018 were extracted. And we used IQVIA data to determine the market share and sales growth rate of 48 original drugs, whose generic drug launched for the first time in the same molecule market, and whose sales data over five years after first generic entry were available. We analyzed the differences by the attribute of variables. Results: The sales volume of original drugs in the fifth year (Q 20) had an average growth rate of 150.6% compared with that before the first generic drug launched, indicating a continuous growth. The average market share of original drugs in the fifth year (Q 20) decreased to 70.6%, but it was higher than previously reported research results in Korea and other countries. Differences were observed across the category of attribute. Conclusion: This study demonstrated that while market share of original drugs is decreasing, the sales volume increased continuously until the fifth year, differently from those of other countries. Variations in sales patterns by attributes reflect unique dynamics in Korea. © The Author(s) 2025.