InSite Vision Inc. et.al v. Sandoz, Inc., (Fed. Cir. April 9, 2015) 

Affirming the finding by the U.S. District Court for the District of New Jersey that defendant failed to prove Plaintiffs’ patents directed to methods of treating ocular infections with azithromycin are invalid, the U.S. Court of Appeals for the Federal Circuit determined Sandoz Inc. did not show by clear and convincing evidence that it would have been obvious to one of ordinary skill in the art to use azithromycin to topically treat ocular infections. The court also upheld the district court’s refusal to admit into evidence a late-proffered file history of a European counterpart patent. InSite Vision Inc. v. Sandoz, Inc., 783 F.3d 853 (Fed. Cir. April 9, 2015) (J. Linn).

This case involves U.S. Patent Nos. 6,861,411, 6,239,113, 6,569,443 and 7,056,893 covering InSite Vision’s topical azithromycin solution, Azasite® (azithromycin ophthalmic solution). Sandoz stipulated to infringement but contested the validity of the asserted claims based on obviousness. At issue was whether the district court “mis-framed” the obviousness inquiry by adopting InSite Vision’s broader characterization of the problem at the time of the invention of “improved topical treatments for ocular infections” as opposed to the more narrow problem proposed by Sandoz of “topically administering azithromycin to treat conjunctivitis.”

The Federal Circuit determined that the district court did not clearly err in framing the obviousness inquiry finding that persons of ordinary skill in the art would not have developed formulations that only treated conjunctivitis and not corneal infections given the concerns of conjunctival infections spreading to the cornea. When considering motivation in an obviousness analysis, the court explained, the proper inquiry is not the specific problem solved by the invention. Defining the problem in terms of the solution results in an improper hindsight selection of relevant prior art. The court noted that Sandoz’s overly narrow approach reflected hindsight in defining the problem. The proper inquiry, it explained, is whether a person skilled in the art “would have been motivated to combine the teachings of the prior art references to achieve the claimed invention, and…would have had a reasonable success in doing so.”

On the merits of the obviousness determination, the Federal Circuit noted that, although azithromycin was known to treat bacterial infections, it was considered a poor choice for treating topical ocular infections based its molecular weight, charge and insolubility in water—which raised concerns of whether it could penetrate the ocular tissue. The court also determined that the evidence presented did not demonstrate a correlation between oral and topical ophthalmic drug penetration. Thus, the fact that azithromycin was successful when administered systemically did not ensure that topical administration would penetrate the eye tissue.

The court also upheld the district court’s decision refusing Sandoz’s request to amend its exhibit list to introduce into evidence the file history of a European counterpart patent of one of the asserted patents. Sandoz sought to amend its exhibit list after the pre-trial conference and following briefing on various motions in limine. The file history purportedly chronicled the dates and contents of a meeting relevant to Sandoz’s obviousness case. Relying on law from the U.S. Court of Appeals for the Third Circuit, the court concluded that the district court did not abuse its discretion in excluding the file history into evidence as untimely. The court agreed with the district court that admitting the European Patent Office (EPO) file history into evidence on the eve of trial would be prejudicial in requiring InSite Vision to prepare arguments explaining the differences between European and U.S. patent law and the significance of the statements in the prior proceedings.