AstraZeneca Pharma. LP v. Anchen Pharma., Inc.
April 09, 2012
Drug Product and Patent(s)-in-Suit: Seroquel® XR (quetiapine fumurate); U.S. Pat. No. 5,948,437 ("the '437 patent")
Nature of the Case and Issue(s) Presented: AstraZeneca Pharma. LP ("AZ") accused various generic manufacturers of infringing its '437 patent. Claims 1-13 of the '437 patent were asserted against Anchen and Mylan. Claims 1, 2, 10-13 were asserted against Osmotica and Torrent. Anchen, Osmotica and Mylan have conceded infringement but assert, along with Torrent, that the '437 patent is obvious. During a 12-day bench trial, AZ presented its infringement evidence against Torrent, and the defendants presented evidence in support of their invalidity defense.
The issue in AZ's infringement claim against Torrent concerned (i) whether the ingredient in Torrent's ANDA product that caused the sustained release, namely FMC's Viscarin 209, is a "gelling agent" within the meaning of claim 1 of the '437 patent; and (ii) whether Viscarin 209 is the equivalent of the gelling agent recited in claim 2. The Court answered both questions in the affirmative. As for defendants' invalidity defense, the Court found that defendants had not established by clear and convincing evidence that any of the claims of the '437 patent were invalid as obvious.
Why AZ Prevailed: The Court construed "gelling agent" to mean "any substance which forms a gel when in contact with water." Although FMC promotes Viscarin 209 as a "non-gelling carrageenan" (Torrent's argument for non-infringement), AZ's expert performed a test that FMC uses for measuring the "gel strength" of Viscarin 209. In performing this test, a plunger is pushed into the test material and the force necessary for the plunger to enter the material is the measure of the gel strength of the material. Viscarin 209 exhibited a break-force strength of 20-50 g. Although evidence showed that this figure was significantly lower than what would be obtained with strong gelling carrageenans, AZ's expert testified that any measured break-force strength means a gel was formed. This testimony was corroborated by an FMC representative who stated that Viscarin 209 formed a gel, albeit a weak one. Coupled with the finding that Viscarin 209 was equivalent to AZ's HPMC, the Court found that Torrent's ANDA product infringed the claims of the '437 patent.
Defendants relied on eight pieces of prior art. Though AZ did not contest that every element of the asserted claims was described in the prior art, no single reference described the sustained-release of quetiapine or its use in treating psychotic states. Moreover, the Court found that a person of ordinary skill in the art would not have been motivated to combine the prior art references or would have had any reasonable expectation of success in doing so for purposes of describing the subject matter of the claims of the '437 patent. Based on various distinctions between the art and the claimed invention-the active ingredients are different; different analytical characteristics (e.g., solubility factor, not gel strength); different indications; different dosages, etc.-the Court found that only through the "application of hindsight" would a person of ordinary skill in the art combine certain of the prior art references in the hopes of achieving the disclosed inventions of the '437 patent. "The Court finds that such a conclusion was based primarily upon hindsight and, further, failed to consider certain obstacles that a [person of ordinary skill] would have faced in trying to develop any kind of sustained release form of a drug with the physical and biological properties of quetiapine."
Next, the Court addressed secondary considerations of non-obviousness. In May 1997, there was a recognized but unmet medical need for an effective drug therapy for the treatment of bipolar depression. The Court found that Seroquel XR satisfied that unmet need. First, Seroquel XR has a unique and unexpected combination of FDA approvals that are based on the unexpected results of clinical trials. It is the only drug ever approved for the treatment of bipolar disorder, bipolar depression, and major depressive disorder. Second, Seroquel XR had a sedation profile that was unexpectedly superior to instant release Seroquel. Seroquel XR is a commercial success. Its cumulative sales since launch in 2008 through March 2011 totaled $1.7 billion, total prescriptions have increased substantially, and its market share has increased within the antipsychotic drug market. All of those reasons further evidenced the '437 patent's validity.
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