Success PuzzleIn what appears to be only the second instance¹ to date, evidence of secondary considerations helped a Patent Owner defend against a Petitioner’s obviousness challenge during an IPR proceeding.  In Phigenix, Inc. v. Immunogen, Inc., the Board issued its final written decision and held that each of the eight challenged claims were not unpatentable, finding the Patent Owner “advances persuasive evidence” regarding the prior failure of others and the long-felt need in the industry. Phigenix, Inc. v. Immunogen, Inc., IPR2014-00676, Paper 39, (“Dec.”) (PTAB Oct. 27, 2015).

The patent at issue relates to antibody-toxin immunoconjugates for use in treating human tumors, in particular an anti-ErbB antibody linked to a maytansinoid toxin. Each challenged claim 1-8 recites an immunoconjugate including “huMAb4D5-8” humanized anti-ErbB2 antibody, which is commercially marketed under the name HERCEPTIN®. Dependent claim 8 further requires that the maytansinoid is “DM1,” and this claim covers the commercial immunoconjugate product Kadcyla®.

The Petitioner argued that the claims were obvious because a person having ordinary skill would have had reason to substitute HERCEPTIN® in place of a mouse monoclonal TA.1 antibody known in the art because (1) it was known that, for clinical applications, humanized antibodies were preferred over mouse counterparts, (2) HERCEPTIN® had been approved by the FDA to treat breast tumors in humans, and (3) clinical studies indicated that HERCEPTIN® worked well in combination with chemotherapy agents similar to maytansinoids, for the treatment of breast cancer.  Dec. 15 (citing Petition, Paper 5, “Pet.” 14-15).

The Patent Owner argued that HERCEPTIN® would not have been considered an acceptable substitute for the mouse antibody because HERCEPTIN®-maytansinoid immunoconjugates would have been expected to exhibit unacceptable levels of toxicity.  Dec. 16.  In support of its arguments, the patent owner submitted evidence including an expert declaration presenting evidence of objective indicia of non-obviousness.

In its reply brief, the Petitioner argued that the Patent Owner failed to establish that there was a nexus between the objective indicia evidence and claim 8, however, the Petitioner did not offer any additional expert testimony to rebut the Patent Owner’s evidence of objective indicia of non-obviousness.  Although the PTAB rules discourage the presentation of new evidence with a reply brief, here it may have been appropriate to present rebuttal evidence and testimony in reply, to respond to the objective indicia evidence submitted with the Patent Owner’s response.

Board’s Analysis
In concluding that the Petitioner had not established that claims 1-8 were obvious, the Board noted that the Patent Owner advanced “persuasive evidence” that the prior art indicated that the claimed immunoconjugates would have been expected to have unacceptable levels of toxicity, and that persons of ordinary skill would not have had a reasonable expectation that the claimed immunoconjugate would have been useful for treating tumors in humans. With respect to claim 8, the Board determined that the Patent Owner provided substantial evidence of objective indicia of non-obviousness, including unexpected results, long-felt, unmet need, praise in the field, and commercial success of the Kadcyla® product.

patent owner “advances persuasive evidence” that ordinary artisans would not have had a reasonable expectation of success

It is unclear how rebuttal evidence from an expert, if presented, could have affected the Board’s conclusions regarding these secondary indicia, but it also may be a moot point given the Board concluded claim 8 is non-obvious regardless of these indicia.  The key here may simply be that there is now a second final written decision in which the Board has indicated that objective indicia of non-obviousness was sufficient to rebut an obviousness challenge.



¹In what appears to be the first instance, in Intri-Plex Techs., Inc. v. Saint-Gobain Performance Plastics Rencol Ltd., the Board held that evidence of commercial success and copying weighed in favor of finding that the patented invention is non-obvious.  See IPR2014-00309, Paper 83 (PTAB Mar. 23, 2015).