Purdue Pharma L.P. v. Varam, Inc.

Patent-in-suit not invalid, particularly in view of the same or similar arguments being raised, and rejected, in previous actions.

July 15, 2013

GENERICally Speaking

Case Name: Purdue Pharma L.P. v. Varam, Inc., Civ. No. 04 Md. 1603 (SHS), 2013 U.S. Dist. LEXIS 58592 (S.D.N.Y. Apr. 15, 2013) (Stein, J.)

Drug Product and Patent(s)-in-Suit: OxyContin® (oxycodone); U.S. Patent No. 5,508,042 (“the ’042 patent”)

Nature of the Case and Issue(s) Presented: Varam brought summary-judgment motions of invalidity and noninfringement of the ’042 patent. Varam relied principally on the ’598 patent, which claimed a particular formulation to be used for controlled-release oral administration of drugs, not just oxycodone. But twice before, the court had issued opinions concerning the ’042 patent. On one occasion, Purdue moved for a preliminary injunction and the court found that (i) it was likely to succeed on the merits of its infringement claim and (ii) the ’042 patent was not anticipated by the ’598 patent. In a separate action, three years after the preliminary injunction hearing referenced above, the court held a trial and found the patents (including the ’042 patent) infringed, but invalid due to Purdue’s inequitable conduct during prosecution. The Federal Circuit affirmed the infringement ruling, and ultimately vacated the inequitable conduct finding. The court denied Varam’s instant motion.

Why Purdue Prevailed:  The district court and Federal Circuit have already construed the two claims of the ’042 patent at length. Varam argued that the court should reevaluate its conclusion that the preambles do not limit the ’042 patent’s claims. But the court found that the Federal Circuit explicitly held that the prosecution history did not limit the substantive terms of the asserted claims, and therefore would not “smuggle” that language back into the claims. Next, Varam argued that the ’598 patent anticipates the ’042 patent because “all prior art controlled release oxycodone-containing tablets that have been taught by the ’598 patent and which were analyzed for their clinical properties have been found to inherently anticipate the ’042 patent claims.” Varam’s argument ignores the first court decision referenced above when Purdue sought a preliminary injunction against Boehringer. The court held that Varam presented considerably less evidence than the court considered during the Boehringer proceeding, yet Varam seeks a more favorable result for itself. Because the court already considered this evidence once before, it found that a material question of fact existed as to whether the in vitro teachings of the ’598 patent anticipate the in vivo limitations of the ’042 claims.

By relying on the same prior art in support of its obvious defense, the ’598 patent, the court found the genuine issues of material fact remain as to the scope and content of the ’598 patent’s teachings.

The court equally disposed of Varam’s contention that the ’042 patent fails to satisfy the written description requirement. Example 18 of the ’042 patent describes an in vivo study of a 10 mg controlled-release oxycodone tablet that produced plasma concentrations and time ranges that fall within the scope of the asserted claims. In addition, the ’042 patent details repeated dose studies that conform to the claimed invention. That alone precluded the court from granting Varam’s summary-judgment motion for failure to meet the written description requirement.

Finally, Varam argued that the asserted claims are invalid on double-patenting grounds. Varam relied on three patents in support of its argument. The first patent claims in vitro characteristics of oxycodone. The court cannot evaluate whether in vitro teachings make in vivo limitations in the ’042 patent obvious, therefore, Varam has not met its clear and convincing burden as to its double-patenting argument in this first instance. The second patent covers inventions that are the different from the ’042 patent—as evidenced by the restriction requirement raised by the USPTO, thus, there is no same-invention type double patenting. Finally, the third patent issued almost a year after the ’042 patent was approved. Because Varam cannot turn back time to find a way to use the third patent to invalidate the earlier-applied-for and earlier-issued ’042 patent, there cannot be double patenting.

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