In July of 2015, Sanofi filed petition for an inter partes review (IPR2015-01624) for 15 claims of U.S. Pat. No. 6,331,415 (“Cabilly II”).  In the antibody field, the Cabilly family of patents is well known and is believed to bring in millions of dollars in revenue annually.

On February 5, 2016, the Board decided to institute an inter partes review for 11 of the 15 challenged claims, finding that there was a reasonable likelihood that Sanofi would prevail on a theory of obviousness of at least one challenged claim.

In the initial petition, Sanofi asserted that a number of claims of Cabilly II, which relate generally to expression of DNA sequences encoding immunoglobulin heavy and light chains in a single cell, were anticipated and obvious over “Bujard”.  The Board declined to institute an IPR based on anticipation, finding that Sanofi’s theory required drawing inferences under an analysis “within the purview of obviousness, not anticipation.”  In particular, the Board found that Sanofi relied on distinct disclosures in Bujard of (i) different genes under the same promoter in general, and (ii) the structure of immunoglobulins as including heavy and light chains.  The Board held that the skilled artisan would have had to make choices based on inferences drawn from sources outside of Bujard in order arrive at different heavy and light chain genes being present in the same vector and expressed in the same cell.

However, the Board found that Sanofi had a reasonable likelihood of success of prevailing on obviousness in view of Bujard in combination with either of two secondary references.  In particular, in view of expert declarations, the Board found that Bujard suggested incorporating genes encoding a plurality of subunits of a multimeric protein into a vector in a single cell (and also recognized immunoglobulins in general), and that the secondary references taught combining subunits in vitro to produce multimeric proteins.  The Board noted that Bujard offered more specific teachings than references considered by the PTO in a previous reexamination proceeding.

The Board declined to institute a second obviousness challenge, finding it redundant.

If the IPR does not settle in the coming months, it will be interesting to see how this patent fairs in an IPR proceeding, as other patents in the Cabilly family have been the subject of numerous litigations and other PTO proceedings (including an interference and a re-examination).