Mayer Brown secured a victory before the United States Patent and Trademark Office on behalf of Vertex Pharmaceuticals and ViiV Healthcare in an Inter Partes Review (IPR) brought by Lupin Limited. In the IPR, Lupin challenged all claims of Vertex’s US Patent No. 6,436,989 as obvious in light of the prior art. The ‘989 patent protects Lexiva®, a key HIV treatment developed and marketed by ViiV Healthcare.

On July 9, 2015, the Patent Trial and Appeal Board (PTAB) declined to institute IPR proceedings on the claims that encompass fosamprenavir, the active ingredient in Lexiva® and its use to treat HIV infection, finding no reasonable likelihood that Lupin would prevail. The decision impedes any attempt by Lupin to bring a generic fosamprenavir product to the market.

This is a significant victory for pharmaceutical patents. Based on the evidence submitted by Vertex and ViiV, the PTAB found the development of a therapeutically effective prodrug “not at all predictable” and consequently, there was no reasonable expectation of success that the prodrug fosamprenavir would provide successful treatment of HIV infection. In addition, the PTAB found that the patent owner’s objective evidence of nonobviousness, including improved pharmacokinetics and resistance profiles, overcame the petitioner’s evidence of obviousness—a rare outcome before the PTAB.

The Intellectual Property litigation team included New York partners Lisa Ferri and Brian Nolan, Chicago counsel Jonathan Kim and New York associate Neil DuChez.