Many biosimilar applicants have resorted to inter partes review (IPR) proceedings to challenge innovator patents as an alternative forum to district court litigation under the BPCIA.  For those biosimilar applicants that choose to engage in the “patent dance” and the resulting district court litigation, an IPR can also provide another arrow in their quiver against patent owners.  Apotex recently employed this dual-front strategy, taking aim at an Amgen patent in an IPR petition after being sued under the BPCIA.

On August 5, 2016, Apotex filed a petition (IPR No. 2016-01542) with the Patent Trial and Appeal Board (PTAB) for IPR of all twenty-four claims of U.S. Patent No. 8,952,138, relating to methods of refolding proteins expressed in a non-mammalian expression system.  Amgen owns the ’138 patent, which it has asserted against Apotex in pending biosimilar patent litigation in the District Court for the Southern District of Florida (Civil Action No. 15-CV-61631-JIC).  In its IPR petition, Apotex asserts that each claim of Amgen’s ’138 patent is invalid on grounds of anticipation or obviousness.

Apotex’s new IPR petition is the latest salvo in its attempt to clear the path of patents blocking its biosimilar version of Amgen’s Neulasta® (pegfilgrastim), a recombinantly-expressed protein approved by the FDA to decrease the incidence of infection in patients receiving myelosuppressive anti-cancer drugs.  The district court previously granted Amgen’s request for a preliminary injunction, affirmed by the Federal Circuit (as we previously reported here), enjoining Apotex from launching its pegfilgrastim product until it receives FDA approval and provides at least 180 days notice before the date of first commercial marketing.  Following a bench trial held last month, the district court granted Amgen’s motion pursuant to Fed. R. Civ. P. 52 for judgment on partial findings that the asserted claims are not invalid on grounds of anticipation, obviousness, written description, and indefiniteness.  The district court has yet to address Apotex’s enablement defense.  The post-trial briefing is also underway with respect to Apotex’s motion for judgment of non-infringement.

Apotex waited until the very last minute to file its IPR.  Under 35 U.S.C. § 315(b), a party cannot file an IPR petition more than one year after “the petitioner is served with a complaint alleging infringement of the patent” at issue in the petition.  Amgen filed its district court complaint against Apotex on August 6, 2015, and that same day, Apotex elected to waive service of the summons, starting the one-year clock.  Apotex filed its IPR petition on August 5, 2016 – the day before the one-year mark.  Notably, Amgen’s ’138 patent issued on February 10, 2015, after Apotex had initiated the “patent dance” and only a few weeks before Amgen provided, pursuant to the BPCIA, its list of patents it believed were infringed.

With its IPR petition, Apotex has another shot at invalidating Amgen’s ’138 patent based on anticipation or obviousness, despite the district court’s ruling that Apotex failed to meet its burden of establishing those defenses.  Although the district court construed certain terms of the ’138 patent under the so-called Phillips standard, the PTAB is not bound by the district court’s constructions and instead must apply the “broadest reasonable interpretation” of the claim terms.  37 C.F.R. § 42.100(b).  Moreover, under 35 U.S.C. § 282(a), district courts must presume that patents are valid and accused infringers have the burden to prove otherwise by clear and convincing evidence.  There is no such presumption during proceedings at the PTAB.  Rather, the PTAB is to determine whether claims are invalid based on a mere preponderance of the evidence.

Amgen has until early November 2016 to file a preliminary response to Apotex’s IPR petition.  The PTAB then has an additional three months to decide whether to institute a trial on any of the grounds raised in Apotex’s petition.  If the PTAB were to institute a trial, a final written decision must issue no later than twelve months after the date of the PTAB’s institution decision.

Amgen and Apotex may now find themselves in a race to final judgment in the parallel proceedings.  That is, despite the district court’s prior ruling on the validity of the ’138 patent, Amgen could still end up on the losing end if the PTAB institutes an IPR trial and the patent is invalidated before entry of final judgment in the district court litigation.

We will continue to follow developments in this case and update this post as appropriate.