In a recent decision, a district court in the District of Delaware applied estoppel under 35 U.S.C. § 315(e)(2) to a defendant in Hatch-Waxman litigation, two and half years after the court conducted a bench trial on validity. See Novartis Pharm. Corp. v. Par Pharm. Inc., No. 14-1289-RGA, ECF No. 198 (D. Del. Apr. 11, 2019) ("Slip Op.").
Between October 2014 and January 2015, Novartis filed three suits against Par for its submission of Abbreviated New Drug Applications ("ANDAs") seeking FDA approval of generic versions of Novartis's ZORTRESS® (everolimus) and AFINITOR® (everolimus) tablets. Novartis also sued Breckenridge and West-Ward for their ANDA filings relating to everolimus tablets. The defendants stipulated to infringement of the asserted U.S. Patent No. 5,665,772 ("the '772 patent"), but contested the validity of asserted claims 1-3, 7, and 10 in a four-day bench trial in late August and early September of 2016, raising invalidity challenges including obviousness based on twenty-seven prior-art references and obviousness-type double patenting ("OTDP").
Meanwhile, in October 2015, Par petitioned for inter partes review ("IPR") of claims 1-3 and 8-10 of the '772 patent on grounds of obviousness. After the Patent Trial and Appeal Board ("Board") instituted review in April 2016, Par filed another four IPR petitions with joinder motions seeking to join the instituted IPR. In October 2016, the Board instituted the two IPRs that challenged claims 1-3 and 8-10 and granted the related joinder motions, but denied institution and joinder of the two IPRs challenging claim 7 of the '772 patent because Par failed to explain why it did not petition for IPR of claim 7 in its first petition.
In March 2017, the district court issued a post-trial opinion holding the asserted claims of the '772 patent invalid for OTDP, but did not address the defendants' obviousness challenges. Novartis appealed, and the Federal Circuit reversed the district court on OTDP. While the appeal was pending, in January 2018, the Board issued a final written decision upholding the patentability of claims 1-3 and 8-10. After remand from the Federal Circuit, and on Novartis's motion for estoppel, the district court held that Par was estopped under § 315(e)(2) from challenging the validity of claims 1-3 and 8-10 of the '772 patent on grounds of obviousness.
First, the district court held that estoppel applies even to prior-art references that were not raised in the IPR...