ABiosimilars are biologic drugs that are "highly similar" to a previously approved biologic (also known as reference innovator product).

A biosimilar must undergo a stringent similarity testing at every step of its development to demonstrate that potential differences from the reference product are not clinically meaningful with regard to quality, safety, and efficacy [EMA], or safety, purity, and potency.

The binding between a biosimilar and its target antigen (and Fc receptors) is considered an important indicator to its efficacy. ACRO Biosystems has developed high quality target antigen proteins and Fc receptor proteins to facilitate biosimilar research.