Mayer Brown secured a final 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 claims 2, 3 and 10-12 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 28, 2017, the Patent Trial and Appeal Board (PTAB) issued a final written decision concluding that Lupin had failed to satisfy its burden of demonstrating that the challenged claims were obvious, thus upholding the patentability of the patent claims that encompass fosamprenavir, the active ingredient in Lexiva® and its use to treat HIV infection. The decision impedes any attempt by Lupin to gain early entry into the market with a generic fosamprenavir product and marks the end of the five-year battle to protect the patents covering Lexiva® from multiple generic challengers.

This is a significant victory for pharmaceutical patents. Based on the evidence submitted by the patent owner, 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 resistance profile, pharmacokinetics and side effect profile overcame petitioner’s evidence of obviousness—a rare outcome before the PTAB.

The New York-based Intellectual Property litigation team included partners Lisa Ferri and Brian Nolan and associate Scott McMurry.