Fresenius files IPR against Amgen

Fresenius Kabi has submitted a petition for inter partes review (IPR) of US patent number 9,856,287, a patent owned by  Amgen.

The petition, which Fresenius submitted on Sunday, April 14, asked the Patent Trial and Appeal Board to institute review of the patent that covers methods of refolding proteins using a chemically controlled redox state.

Allergan’s patent covers its chemotherapy-easing drugs Neupogen (filgrastim) and Neulasta (pegfilgrastim). Fresenius is currently developing a biosimilar version of Neulasta.

According to the petition, the redox refolding method occurs where unfolded proteins are

incubated in a buffer containing amounts of an oxidant and a reductant that permits the proteins to refold into their native 3D structure.

“This basic ‘redox’ refolding method was in common use as of June 22, 2009, the earliest possible filing date of the patent, and scientists routinely tailored the compositions of their redox buffers to optimise the yield of properly refolded proteins,” claimed Fresenius.

Issued in January 2018, the ‘287 patent claims priority to a provisional application filed in June 2009.

Germany-based Fresenius alleged that each of the challenged claims are anticipated by prior art.

The ‘287 patent is currently the subject of litigation and post-grant proceedings, in disputes between Amgen and Adello Biologics and Apotex.

In August last year, Amgen sued Apotex over the company’s efforts to market biosimilar versions of Neupogen and Neulasta, alleging infringement of the ‘287 patent.

This was the third time that Amgen had taken Apotex to court under the Biologics Price Competition and Innovation Act (BPCIA) of 2009, in relation to the proposed biosimilars.

The ‘287 patent didn’t issue until after Amgen and Apotex had completed the ‘patent dance’ exchanges under the BPCIA in connection with the two earlier actions.

Back in July 2016, one of these cases (concerning the biosimilar of Amgen’s Neulasta) was  decided on by the US Court of Appeals for the Federal Circuit, which found that bisoimilar companies must always notify brand name rivals 180 days before launching their products.

Apotex  filed a petition for a writ of certiorari, but the US Supreme Court rejected its application.

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