Abstract
Bioequivalence studies are designed to compare two medicines generic drug and the original drug, that both are equal in the rate and extent to which the active pharmaceutical ingredient (API) becomes available at the site(s) of drug action. Bioequivalence study increases people’s trust in generic drugs. Bioequivalence studies are conducted in human trials in which each subject receives the same dose of each drug under similar experimental conditions. Bioequivalence is concluded when the absorption rate of the generic drug is not significantly different from of the original drug or reference drug. These studies must be approved by the research ethics committee to ensure that the research is conducted in accordance with ethical guidelines and that volunteers are adequately protected. The Institute for the Development of Human Research Protections (IHRP) has continuously reviewed and approved research involving human subjects to ensure that the research protocol meets the ethical guidelines. IHRP approval triggers bioequivalence studies in Thailand. This study aims to explore the bioequivalence projects submitted to and approved by IHRP during 2008-2021 of their success and registration by the Thai Food and Drug Administration (FDA) and local production of new generic drugs and to estimate the total cost saving if all original products were substituted by the equivalent generic medicines Quantitative statistics are used for the analysis. The results show that 14 years between 2008 and 2021, there were 737 research project proposals submitted to the IHRP, among this number, two projects withdrew. After the committee meeting, most of them (79.7%) immediately obtained ethical approval. A total of 507 studies, or two-thirds of the total projects (69.0 percent), reported successful bio-equivalent studies. There were 106 projects withdrew from conducting bioequivalence studies, while 122 projects did not provide the updated status of the studies. Among the successful studies, 53 projects received marketing authorization numbers. Of these, only 22 items have drug price information available. Most of the new generic drugs which were submitted to the IHRP and achieved drug registration numbers had a lower price than other similar drugs in the market that were launched in the same year. This reflects the possibility that the new generic drugs could gain economic savings due to the price differences. The unit price difference varies, ranging from -9.6 baht per unit (one tablet/ capsule/ milliliter) to 1,388.5 baht per unit. The highest and lowest total savings per unit of all 22 items were 1,626.4 baht and 149.2 baht per unit of medicine, respectively. However, researchers cannot access to FDA database on quantity of local manufacturing of these 22 generic drugs, it is not possible to calculate the total cost saving if original versions were fully replaced by generic version. Only four items including Sofosbuvir 400 mg, Gabapentin 300 mg, Favipiravir 200 mg, and Tenofovir+Emtricitabine 300/200 mg had the completed data of prices and quantity reported by the Government Pharmaceutical Organization. The maximum of value saving from these drugs were 1,087.4 million baht, 395.3 million baht, 93.8 million baht, and 0.9 million baht respectively. Therefore, the increased number of new generic drugs could significantly reduce cost of medicines spent by the country. This study highlights that the approval process of IHRP on bioequivalence studies is quick and it facilitates the process of having new generic medicines to the market which further resulted in huge cost saving on pharmaceutical spending of Thai health systems. The study also pointed out the opportunity for further research, such as challenges on conducting bioequivalence, strengths or success factors and weaknesses in obtaining marketing authorization numbers. These issues can be the evidence to support the development of the drug registration system in Thailand.
