Bioequivalence is the regulatory science of establishing that one product is/should be equivalent to another one in terms of clinical safety and efficacy. Two products that are bioequivalent to each other can be classified as being interchangeable by a regulatory agency because they will/should lead to the same efficacy and safety clinically. In its simplest form and for the simplest cases, bioequivalence can be established using in vitro data only. For the majority of times, one or two equivalence pharmacokinetic (PK) study(ies) where two formulations of the same active ingredient are determined to have the same rate and extent of exposure (Cmax and AUCt) in healthy volunteers will be needed. Sometimes bioequivalence will need to be established using both equivalence PK and clinical therapeutic equivalence studies. For biologics, bioequivalence is more appropriately referred to as biosimilarity because biologics can be therapeutically similar to one another but not truly identical structurally and physico-chemically. Demonstrating biosimilarity between two biologics can be a complicated exercise that may necessitate many different PK, pharmacodynamic, and therapeutic equivalence studies as well as documentation of similar immunogenicity.
Bioequivalence or biosimilarity studies are also required when bridging of safety and efficacy data between two formulations of the same drug/biologic is needed. This applies to all generic submissions, but also to a vast majority of new drug/biologic submissions when bridging to a previous formulation is needed in terms of clinical safety and efficacy.
The Bioequivalence focus group provides a forum to discuss the scientific issues relating to the demonstration of bioequivalence and biosimilarity that allow for sound regulatory policy decisions. Some of the topics for discussion include PK, statistical designs, and metrics for equivalence of different dosage forms such as systemically or locally acting oral, topical and inhalation products, ophthalmic products, injectables as well as equivalence of highly-variable drugs, multiphasic extended-release products, biosimilars, and others.
Please contact the focus group chair or AAPS if you are interested in being involved in the Bioequivalence focus group or would like more information.
Section affiliations: PPDM | RS