Travatan Z® Patent Survives IPR: A Lesson in Successfully Arguing Hindsight Bias

September 27, 2018 – Article

Hindsight bias is not simply an old chestnut argued ad infinitum in response to obviousness challenges. In this week’s final written decision in IPR2017-01053 upholding all claims of U.S. Patent No. 8,268,299, the PTAB illustrated that—under the right circumstances—this argument can have teeth.

No Obviousness in View of Hindsight Bias

The ’299 patent—covering Alcon’s Travatan Z®, an ophthalmic drug used to treat certain types of glaucoma and other causes of high pressure inside the eye—was challenged by generic Argentum Pharmaceuticals as obvious based on numerous reference combinations, all based on the Schneider primary reference. Argentum argued that a person of ordinary skill (“POSA”) would have selected Schneider's Formulation A as the starting point for modification, and then detailed the six modifications necessary to arrive at the specific limitations of the ’299 patent's claim 1. Specifically, Argentum argued that, although a POSA would desire to retain as much of Schneider’s original composition as feasible, a POSA would also (1) replace benzalkonium chloride with zinc ions; (2) replace mannitol with sorbitol; (3) add propylene glycol; (4) adjust the amounts of zinc, sorbitol, and propylene glycol to fall within specific ranges required by claim 1; (5) remove EDTA; and (6) limit anionic species present in the composition to the low concentration recited in the claim.

Alcon argued that Argentum failed to show that a POSA would have reason to combine these references in the claimed manner other than based on hindsight gleaned from the invention, and the PTAB agreed.

In discussing the first modification, the PTAB noted that replacing benzalkonium chloride, a conventional preservative, with zinc, was a more complicated and less obvious route than selecting one of the many conventional benzalkonium chloride alternatives known in the art, and as such “a glimmer of doubt creeps in, regarding whether Petitioner's selection of zinc is driven by disclosures in the prior art or impermissible hindsight reconstruction.” FWD, 10. The PTAB similarly attacked Argentum’s logic (or lack thereof) for the remaining modifications, noting that its conclusory opinion testimony was not persuasive, and that in several instances, the references themselves taught away from Argentum’s proposed modifications.

After considering the first three modifications, the PTAB noted that the “glimmer of doubt, regarding impermissible hindsight, glows brighter.” Id., 13. And after considering all six modifications, the Board found that the “steadily brightening glimmer of doubt catches fire. The challenge appears to be based on impermissible hindsight rather than a course recommended by the combined disclosures of the prior art or the understanding of [a POSA].” Id., 17. This is insufficient to support obviousness, because, as established in KSR, “a patent claim ‘is not proved obvious merely by demonstrating that each of its elements was, independently, known in the prior art.’” Id., 25.

Secondary Considerations

Although it appears that the PTAB would have confirmed the patentability of the claims on this point alone, Alcon also submitted several types of secondary consideration evidence that the PTAB found persuasive. Although I have previously explained that evidence of commercial success very rarely wins the day, Alcon provided evidence that the commercial success of Travatan Z® is attributable “to the only material difference” between Travatan Z® and the original Travatan®; that is, the zinc-based preservation system claimed in the ’299 patent. Argentum attempted to diffuse this argument by arguing that any commercial success was attributable to broad blocking patents, but the PTAB found that Argentum failed to “explain how or why” the alleged patent was a blocking patent and thus did not adequately develop these counter-arguments. Id., 23. Alcon also provided persuasive evidence that Travatan Z® met a long-felt need in the marketplace, and again, Argentum failed to persuasively attack this evidence. The PTAB held that “[t]he objective indicia of nonobviousness, when weighted against Petitioner's relatively weak evidence of obviousness, tip the scales further in favor of Patent Owner.”

Lessons for Practitioners

This case illustrates some best practices for both petitioners and patent owners. For petitioners, reasons to combine references must be clearly articulated. And, care should be taken when selecting the primary reference. Argentum may have fared better by relying on a different starting point: a minimum of six modifications necessary to the base formulation is an uphill battle, even with a strong motivation to combine references and make those modifications.

Alcon’s patent owner response is a great example of how to successfully attack an obviousness challenge. Alcon attacked the merits of each modification and combination and supported its positions with multiple expert declarations. And, Alcon’s secondary considerations evidence was tightly tied to the claimed subject matter, allowing the PTAB to easily associate the advantages of the patent with those secondary considerations. Not all patent owners will be in as good a position as Alcon to argue hindsight, but this case serves as a reminder that, when properly framed, this argument can have teeth.