Pfizer Inc. v. Sandoz Inc

Post-hoc expert conclusions were not sufficient to contradict prior-art publications relating to obviousness.

July 21, 2016

GENERICally Speaking: A Hatch Waxman Litigation Bulletin

Case Name: Pfizer Inc. v. Sandoz Inc., C.A. No. 13-1110-GMS, 2016 U.S. Dist. LEXIS 52762 (D. Del. Apr. 20, 2016) (Sleet, J.)

Drug Product and Patent(s)-in-Suit: Toviaz® (fesoterodine fumarate); U.S. Patents Nos. 7,384,980 (“the ’980 patent”), 7,855,230 (“the ’230 patent”), 7,985,772 (“the ’772 patent”), 8,338,478 (“the ’478 patent”), and 6,858,650 (“the ’650 patent”)

Nature of the Case and Issue(s) Presented: Pfizer manufactures Toviaz, an extended-release tablet used to treat overactive bladder. Defendants each submitted ANDAs seeking approval to manufacture and sell generic fesoterodine. Accordingly, Plaintiffs filed suit. After the parties presented evidence relating to the issue of infringement, the court concluded that the Defendants infringed. After the validity case, the court found that Defendants did not meet their burden to clearly and convincingly establish that the patents-in-suit were obvious.

Why Pfizer Prevailed: Defendants argued that the patents-in-suit were obvious in light of the prior-art molecule tolterodine and its metabolite, 5-HMT. The court found that Defendants’ analysis was too myopic and a person of ordinary skill would not focus only on tolterodine. Instead, a number of other compounds would also be considered.

Moreover, the court was not convinced that a person of ordinary skill would modify the 5-HMT metabolite as called for in the patents-in-suit. Defendants’ expert evidence was based entirely on post-hoc conclusions, while Plaintiffs submitted prior-art publications suggesting that modifying 5-HMT would have no clinical significance. Defendants presented nothing to contradict those publications. Finally, the court found that even if a person of ordinary skill were motivated to modify 5-HMT, the skilled person would not arrive at the chemical structure of fesoterodine as disclosed in the patents-in-suit. Thus, it was not obvious to modify 5-HMT. Accordingly, the patents-in-suit were valid and infringed by Defendants.

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