Basaglar: A Hypersensitivity Reaction

Introduction

The human insulin molecule is composed of a specific sequence of amino acids built in such a way that any change or modification will affect its primary, secondary, or tertiary structure, which in turn can affect the safety and efficacy of the therapeutic protein. As patents on currently available basal insulins begin to expire, biosimilar products will emerge and quickly replace many of these products owing to their favorable pricing profiles. However, biosimilar products are not 100% identical to their reference products because of their complex manufacturing processes from living cells or organisms (1). For that reason, the regulatory requirements for biosmiliars are more complex than for generic molecules. The Biologics Price Competition and Innovation Act of 2009, passed as part of the Patient Protection and Affordable Care Act, allows biosimilar products to be approved by the U.S. Food and Drug Administration (FDA) via an abbreviated pathway (2). Biosimilars must demonstrate no clinically meaningful differences from their reference products in safety, purity, and potency, but they do not have to complete a therapeutic equivalence study. Yet, a major concern with biosimilars is the risk of immunogenicity resulting from variations in manufacturing, and thus clinical studies must be conducted before FDA approval to evaluate potential differences in the incidence and severity of immune responses (3). However, such FDA approval studies may not be sufficient, and post-marketing monitoring of biosimilars is essential for patient safety.

Hypersensitivity reactions to insulin analogs are rare, with only one published case report of a reaction caused by a biosimilar product in China (4). In 2016, Basaglar was the first “follow-on” insulin glargine approved for use in the United States, with an amino acid sequence identical to that of insulin glargine (Lantus) (5). In Europe, this agent is referred to as a “biosimilar,” but because of …