Following a week-long bench trial held last year, the U.S. District Court for the District of Delaware released an opinion (pdf file) on March 31 stating that Takeda's (OTCPK:TKPHF) patents on Prevacid (lansoprazole) are valid and that Teva's (NASDAQ:TEVA) ANDA for a generic version of Prevacid capsules infringes one of the patents. Prevacid, a treatment for acid reflux, heartburn and stomach ulcers, had $3.4 billion in U.S. sales last year.
Takeda asserted U.S. Patent Nos. 4,628,098, covering the lansoprazole compound, and 5,045,321, covering a pharmaceutical composition of lansoprazole, against Teva. Teva conceded that its generic drug product infringes the '098 patent, though it contested infringement of the '321 patent. Moreover, Teva argued that the '098 and '321 patents are invalid for obviousness and unenforceable due to inequitable conduct.
Lansoprazole is a member of a class of drugs known as proton pump inhibitors, or PPIs, which prevent stomach cells from pumping acid into the gastrointestinal tract. The first PPI was timoprazole, which was disclosed and claimed in a patent in 1977. Timoprazole is the basic molecular skeleton upon which every subsequent successful PPI has been based, including omeprazole and lansoprazole. Teva asserted that the lansoprazole compound would have been obvious in view of the prior art disclosure of the timoprazole backbone and the methyl and trifluoroethoxy fluorinated substituents in lansoprazole.
The district court began its analysis of Teva's obviousness argument by citing KSR:
Teva must identify some reason that would have prompted a person of ordinary skill in the relevant field to combine these elements to yield the claimed compounds.The court found that while a person "would have started with a timoprazole skeleton and focused on the four key locations on the skeleton," Teva failed to prove there would have been a motivation
to substitute the trifluoroethoxy substituent, found previously on the benzimidazole ring in the compounds of the [prior art] patent, onto the 4-position of the pyridine ring to form lansoprazole ... or would have had any reasonable expectation of success in doing so.Therefore, the court rejected Teva's argument that the '098 patent would have been obvious.
The court also rejected Teva's argument that the '321 patent, which claims a lansoprazole formulation comprising a basic inorganic salt (to stabilize the active ingredient), would have been obvious. However, the court found that the lansoprazole and magnesium carbonate in Teva's product are not "in contact ... evenly," as required by the claims, and therefore Teva does not infringe the '321 patent.
Finally, the court found Teva's inequitable conduct arguments to be meritless.
Teva immediately announced plans to appeal the district court decision to the Federal Circuit. If the decision is upheld on appeal, Teva will have to wait until at least May 2009, when the '098 patent expires, to market its generic version of Prevacid capsules.