Patent watch: Have the biosimilar floodgates been opened in the United States?

It took 5 years from the effective date of the Biologics Price Competition and Innovation Act (BPCIA) — the legislation introduced to create a pathway for the approval of biosimilar products — for the US Food and Drug Administration (FDA) to approve the first biosimilar product. In March 2015, Sandoz gained approval for filgrastim-sndz (Zarxio), a biosimilar version of Amgen’s filgrastim (Neupogen). Will a flood of other biosimilars follow? There are three main hurdles a biosimilar product must clear to enter the US market — regulatory exclusivity periods, regulatory ‘biosimilarity’ requirements and patent exclusivity periods. The BPCIA provides regulatory exclusivity to reference products by preventing the FDA from approving a biosimilar application until at least 12 years after approval of the reference product. The BPCIA also requires clinical biosimilarity, which the FDA assesses on the basis of “data derived from analytical studies; animal studies; and a clinical study or clinical studies, including the assessment of immunogenicity and [pharmacokinetics] and [pharmacodynamics]”. However, even if a biosimilar product can clear these two BPCIA hurdles, it may face patent infringement litigation, either from the reference product sponsor or from a third party. For example, although Sandoz’s filgrastim-sndz has been approved as a biosimilar of Amgen’s filgrastim, Amgen has asserted that at least one of its patents covers the product, and is seeking to prevent Sandoz from entering the market until that patent dispute is resolved (the patent expires in December 2016). Likewise, Celltrion is seeking approval of a biosimilar of Janssen Biotech’s infliximab (Remicade), but Janssen has asserted that Celltrion’s product infringes six of its patents (which expire in 2015, 2016, 2018, 2022, 2023 and PAT E N T WAT C H