Pfizer Wins Another Round in Norvasc Case as Synthon's Patents Are Found Unenforceable
Synthon IP v. Pfizer, No. 05-1267 (E.D. Va. 2007)
As we previously reported, last year a jury in the Eastern District of Virginia found that Pfizer does not infringe Synthon IP, Inc.'s patent on processes for making the active ingredient in Norvasc (amlodipine besylate) and also that the patent is invalid. Now, following a bench trial in the same court, Judge T.S. Ellis III has dealt a final blow to Synthon by finding its patents unenforceable due to inequitable conduct. Separately, Pfizer has successfully sued Synthon on its own Norvasc patents. Norvasc is an anti-hypertensive drug with $4.7 billion in sales in 2005. According to the Orange Book, Norvasc is slated to lose patent protection in 2007, but has an exclusivity until September 2008 for use in patients with angiographically documented coronary artery disease.
Synthon filed suit against Pfizer in November 2005, alleging that Pfizer infringed Synthon's process patent US 6,653,481 and related compound patent US 6,858,738. Synthon withdrew the '738 patent from the case prior to the jury trial. After prevailing on noninfringement and invalidity of the '481 patent, Pfizer chose to pursue its inequitable conduct claim to "constrain Synthon's efforts to continue harassing Pfizer with amlodipine-related patent litigation." According to Pfizer, Synthon filed a divisional patent application off of the '738 patent and threatened Pfizer shortly before commencement of the trial in the current case with a further lawsuit on any patent granting off of the divisional. Thus, Pfizer pursued its inequitable conduct claim to establish a basis for finding the '481 patent, the '738 patent, and any related patents unenforceable.
In his findings of fact and conclusions of law, Judge Ellis concluded that during prosecution of the '481 patent Synthon failed to disclose to the U.S. Patent Office material prior art (of which it was aware) that established Pfizer's use of the claimed synthetic process (and production of the compound claimed in the '781 patent) years before Synthon's earliest possible conception date. As a result, Judge Ellis found that Synthon consistently misrepresented its synthetic method and compound as novel and as its own invention. Judge Ellis determined that Synthon's misrepresentations and failures to disclose prior art were highly material and not cumulative to other art that Synthon cited to the Patent Office. Judge Ellis therefore declared the '481 and '738 patents unenforceable due to inequitable conduct.
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