Features of Planning and Conducting Bioequivalence Studies with an Adaptive Design for Drug Analogs of Endogenous Compounds

There is a constant interest in the study of drugs that are analogs of endogenous compounds. Guidelines for conducting bioequivalence studies are being updated. Official regulators are holding seminars on the development and study of generic drugs. The goal of the present study is to analyze approved protocols of clinical bioequivalence studies with an adaptive design for drugs that are analogs of endogenous compounds for the period 2015 – 2023. Nine bioequivalence protocols were analyzed. All protocols contained information on the determination of the endogenous background of the analyte being studied and the method for correcting it. An adaptive design did not need to be chosen because information was available on the variability of the studied endogenous compounds. Non-standard designs of the bioequivalence research could be considered for analogs of endogenous compounds, e.g., studies of the comparative pharmacokinetics with a detailed determination of the endogenous levels and with the use of pharmacodynamic endpoints.