Insights into regulatory and design Aspects of bioequivalence trials in Saudi Arabia: A comprehensive analysis

Aim: This retrospective analysis aimed to comprehensively review the design and regulatory aspects of bioequivalence trials submitted to the Saudi Food and Drug Authority (SFDA) since 2017. Methods: This was a retrospective, comprehensive analysis study. The Data extracted from the SFDA bioequivalence assessment reports were analyzed for reviewing the overall design and regulatory aspects of the successful bioequivalence trials, exploring the impact of the coefficient of variation of within-subject variability (CVw) on some design aspects, and providing an in-depth assessment of bioequivalence trial submissions that were deemed insufficient in demonstrating bioequivalence. Results: A total of 590 bioequivalence trials were included of which 521 demonstrated bioequivalence (440 single active pharmaceutical ingredients [APIs] and 81 fixed combinations). The majority of the successful trials were for cardiovascular drugs (84 out of 521 [16.1%]), and the 2 x 2 crossover design was used in 455 (87.3%) trials. The sample size tended to increase with the increase in the CVw in trials of single APIs. Biopharmaceutics Classification System Class II and IV drugs accounted for the majority of highly variable drugs (58 out of 82 [70.7%]) in the study. Most of the 51 rejected trials were rejected due to concerns related to the study center (n=21 [41.2%]). Conclusion: This comprehensive analysis provides valuable insights into the regulatory and design aspects of bioequivalence trials, and can inform future research and assist in identifying opportunities for improvement in conducting bioequivalence trials in Saudi Arabia.