Because biosimilars are relatively new to the United States, drug makers pursuing FDA approval for biosimilars seek additional information about the kinds and quantities of evidence that the agency uses to approve these therapies.
The European Union has swiftly outpaced the United States in the number of biosimilar therapies that it has approved for marketing; the FDA has only approved 7 biosimilars to date, though many additional molecules are being developed with the US market in mind. Because biosimilars are relatively new to the United States, drug makers pursuing FDA approval for biosimilars seek additional information about the kinds and quantities of evidence that the agency uses to approve these therapies.
A new review, appearing in the Journal of Managed Care and Specialty Pharmacy, assesses the evidence that was used in the first 5 biosimilar approvals: filgrastim-sndz (Zarxio), infliximab-dybb (Inflectra), adalimumab-atto (Amjevita), etanercept-szzs (Erelzi), and infliximab-abda (Renflexis). The review draws on data derived from drug-specific FDA approval documents, webcasts, and advisory committee votes; reference product information; evidence used for the extrapolation of indications; and evidence used to demonstrate similarity in terms of analytic and functional characteristics, pharmacokinetics (PK), pharmacodynamics (PD), efficacy, safety, and immunogenicity.
The review’s authors identified 6 key issues from their data:
Finally, the authors note that FDA advisory committee meetings may be slowing the process of biosimilar approval, and suggest that only those biosimilars that have “specific issues” that would warrant convening a committee be subject to such proceedings. The review identifies a second challenge specific to US biosimilar uptake: the long interval between product approval and market availability, which is a phenomenon largely tied to lengthy patent litigation between reference product sponsors and biosimilar developers.