Cadence Pharms., Inc. v. Exela Scis., LLC, No. 11-733-LPS (D. Del.)
On November 22, 2013, the U.S. District Court for the District of Delaware issued a Final Judgment and Permanent Injunction barring Exela from manufacturing a generic version of OFIRMEV®, which is an injectable liquid acetaminophen composition. Judge Leonard Stark held that all fourteen asserted claims from the two patents in suit were not invalid and would be infringed by Exela's generic product. Judge Stark's reasoning was revealed in his November 14 Memorandum Opinion which was unsealed on November 22.
Plaintiff Cadence Pharmaceuticals, Inc. ("Cadence") holds approved NDA No. 022450 for OFIRMEV®, which was approved by the U.S. Food and Drug Administration in November 2010. Plaintiff SCR Pharmatop ("Pharmatop") is a French civil law partnership that owns U.S. Patent Nos. 6,028,222 ("the '222 patent") and 6,992,218 ("the '218 patent"), which are directed to, respectively, a formulation of, and a method for preparing, a liquid acetaminophen (or paracetamol) composition. Paracetamol is the name used outside of the United States for acetaminophen. Cadence is a Delaware corporation based in California that has an exclusive license to the '222 and '218 patents.
In 2011, Cadence and Pharmatop sued Exela Pharma Sciences, LLC, Exela Pharmsci, Inc., and Exela Holdings, Inc. (collectively, "Exela") for patent infringement after Exela notified the plaintiffs that it had filed ANDA No. 203092 seeking regulatory approval for a generic version of OFIRMEV®.
Cadence and Pharmatop had also sued Perrigo Company, and its subsidiaries Paddock Laboratories, Inc. and Paddock Laboratories, LLC. Each of these three parties were dismissed from the suit by a joint stipulation of the parties after the parties settled and entered into a license agreement. Cadence announced in November 2012 that, under the license agreement, Perrigo has the exclusive right of first refusal to negotiate an agreement with Cadence to market an authorized generic version of OFIRMEV® in the United States if Cadence elects to launch an authorized generic version of the product.
After construing the claims in August 2012, the Court conducted a seven-day bench trial in May and July of 2013.
At trial, Cadence and Pharmatop successfully proved by a preponderance of the evidence that Exela's generic version of OFIRMEV® literally infringed all ten asserted claims of the '222 patent. Despite Exela's arguments to the contrary, the plaintiffs successfully proved that in Exela's generic product, sodium ascorbate acted as a "buffering agent" and mannitol acted as a "free radical scavenger" (i.e., an antioxidant). This meant that Exela's generic product met each of the asserted claim limitations.
Although Cadence and Pharmatop failed to prove literal infringement of any of the four asserted claims of the '218 patent, the plaintiffs succeeded under the doctrine of equivalents. The court found no literal infringement because independent claim 1 required the solution to have a dissolved oxygen content of greater than 2.0 ppm prior to the deoxygenation step. Because the evidence at trial showed no substantial difference based on the time at which the oxygen content is reduced to below 2.0 ppm, the court held that Exela infringed under the doctrine of equivalents.
To invalidate the '222 patent, Exela argued that three pieces of prior art—Greek Patent Application No. 870101510, Korean Patent No. 1993-011994, and U.S. Patent No. 5,270,050—rendered the '222 patent anticipated or obvious. Excela's anticipation argument failed because Exela was unable to convince the court that the prior art disclosed a "stable" liquid formulation, as recited in claim 1, the only independent claim at issue in the '222 patent. Exela's obviousness argument failed for the same reason and additionally because the court was persuaded that each of the following secondary considerations supported a finding of nonobviousness: (1) unexpected results, (2) satisfaction of an unmet need, (3) failure of others, (4) commercial success, (5) successful licensing, and (6) praise of others.
Exela was similarly unable to win its argument that the '218 patent was invalid as obvious in view of the '222 patent combined with an article from the 1978 Journal of Pharmaceutical Studies. Importantly, the 1978 article concerned the oxidative degradation of pyrogallol, which is highly sensitive to oxidation, rather than paracetamol, which is not. The court was unconvinced by Exela's argument for two reasons. First, the court found independent claim 1 was valid and nonobvious given the technical differences in degradation of paracetamol compared to the degradation of pyrogallol (hydrolysis instead of oxidation), as well as the technical difficulties of deoxygenation. Second, Cadence and Pharmatop persuaded the court that all six secondary considerations listed above supported the nonobviousness of the '222 patent.
Based on its findings, the court enjoined Exela from producing its generic version of OFIRMEV® until the '222 and '218 patents expire: August 5, 2017 for the '222 patent and June 6, 2021 for the '218 patent.