OBJECTIVES : This study is to investigate the impact of market exclusivity of generic drugs after full introduction of the Korea-U.S Free Trade Agreement adopted Patent-Registration Linkage System in Korea since Mar. 2015.

METHODS : Between Mar. 2015 and 2018, we found a total of 42 approval medicines (5 International Nonproprietary Names, INN), which include the 5 original drugs on the Korea patent List (Green List) and 37 generic drugs acquired first generic advantage with the exception of injections obtained from the Ministry of Food and Drug Administration(MFDS). We analyzed the prescription sales of original and generic drugs by brand names using with UBIST Live data of UBcare. And we estimated the sum of market share of generic applicants in the INN market, and the correlation between the number of generic applicants and the sum of market share of generic applicants in the INN market.

RESULTS : During the study period, the sum of market share of the generic applicants in the INN markets are 3% (Silodosin, Gefitinib, Tenofovir) and 12% (Metformin SR, Febuxostat), respectively. But the number of generic applicants are 1, 10 and 16 at 3% market share and 1 to 9 at 12% market share, suggesting that the number of generic applicant did not vary based when the generic market share changed from 3% to 12%.

CONCLUSIONS : There seems to be a little generic exclusivity in Korea as the prescription is based on the brand name and not on active INN. Although there are some limitations in this study such as the generic drugs acquired first generic advantage are in different therapeutic area and analysis exception injections, we found that the difference of market share of prescription sales acquired first generic advantage didn’t rely on the number of generic applicants.