Abraxis Bioscience, developer of cancer drug Abraxane®, filed suit against Actavis in April of 2016 following its receipt of notice that Actavis sought approval of a generic form of the drug from the FDA. The notice, called a Paragraph IV Certification, represented that Actavis believed the patents covering the drug were invalid, unenforceable, or would not be infringed by Actavis’s generic drug product. Abraxis responded by alleging that the Actavis product would infringe claims of U.S. Patent Nos. 7,820,788 (“the ’788 patent”), 7,923,536 (“the ’536 patent”), 8,138,229 (“the ’229 patent”), and 8,853,260 (“the ’260 patent”).
On April 4, 2017, Actavis filed IPRs against the four patents, challenging all claims which had been asserted in the district court litigation. These became IPR 2017-01100 (“the 1100 IPR”) covering the ’260 patent, IPR 2017-01101 (“the 1101 IPR”) covering the ’788 patent, IPR 2017-01103 (“the 1103 IPR”) covering the ’536 patent, and IPR 2017-01104 (“the 1104 IPR”) covering the ’229 patent. The ’788, ’536, and ’299 patents are all related, claiming priority ultimately to the same provisional application.
The 1100 IPR challenged all claims of the ’260 patent asserted in the district court litigation on grounds of obviousness over four references: Desai, Shively, Liversidge, and Remington. The 1101 IPR challenged all asserted claims but claim 10 of the ’788 patent on grounds of anticipation by Desai, and all asserted claims on obviousness by Desai alone and obviousness by Desai, Kadima, and Liversidge. The 1103 IPR challenged all asserted claims of the ’536 patent on the same three grounds as the 1101 IPR. The 1104 IPR challenged all asserted claims but claim 20 of the ’229 patent on the same three grounds as the 1001 IPR and the 1103 IPR, and challenged claim 20 by obviousness over Desai and the Taxol® Label and by obviousness over Desai, the Taxol® label, Kadima, and Liversidge. All challenges relied on the Desai reference, alone or in combination.
Abraxis filed its Preliminary Response in all four IPRs on July 12, 2017. While the institution decisions were pending, the importance of proving invalidity only increased for Actavis, as Actavis stipulated to infringement in the underlying district court litigation.
October 10 brought good news for Actavis, as the 1101, 1103, and 1004 IPRs received favorable institution decisions, where all grounds alleged were instituted as to all claims challenged. On October 11, however, institution was denied as to all claims challenged in the 1100 IPR.
Viewing the institution decisions as a whole, the Board determined that Actavis showed a reasonable likelihood that the Desai reference, alone or in combination, could render the challenged claims of the ’788 patent, the ’536 patent, and the ’229 patent invalid. Yet the court was not convinced of the same regarding the ’260 patent.
Reviewing all four patents and their challenged claims, the different outcome between the four IPRs seems to largely be due to the varying importance of the stability of the formulations taught by the prior art. While stability was discussed in all four institution decisions, in the 1101, 1103, and 1104 IPRs, it was discussed mainly as a factor in considering whether a person of skill in the art would have had a reasonable expectation of success in creating the claimed inventions.
However, the claims of the ’260 patent at issue in the 1100 IPR contained a limitation not found in the other patents specific to stability: that the formulation would be “stable for at least 3 days” under certain conditions. The Board decided that Actavis failed to establish that this limitation was taught by the asserted combination of references. The Board rejected Actavis’s argument that the formulations in question were inherently stable to the full scope of “all formulations prepared according to the requirements of the challenged claims.” The Board further found that stable formulations in Desai relied upon by Actavis had too many disparities with the claimed formulations to support the challenge.
Ultimately, institution of three of its IPR petitions has placed Actavis in a stronger position. However, the denial of the 1100 IPR could end up a boon for Abraxis, as the Board has shown that the stability limitation of the ’260 patent will be an important part of Abraxis’s defense of the validity of their patent in the ongoing district court litigation.