Par Pharma., Inc. v. TWi Pharma., Inc.

Based on its claim construction, the court denied defendant’s motion for summary judgment of non-infringement, and because the prior art failed to address the food effect that was the central innovation of the patent-in-suit, summary judgment of invalidity was denied.

Fall 2013

GENERICally Speaking

Case Name: Par Pharma., Inc. v. TWi Pharma., Inc., Civ. No. CCB-11-2466, 2013 U.S. Dist. LEXIS 99578 (D. Md. July 17, 2013) (Blake, J.)

Drug Product and Patent(s)-in-Suit: Megace ES® (nanoparticulate formulation of megestrol acetate); U.S. Patent No. 7,101,576 (“the ’576 patent”)

Nature of the Case and Issue(s) Presented: The parties filed cross motions for summary judgment concerning the issues of infringement and invalidity. Additionally, Par, owner of the ’576 patent, filed a motion to strike certain of TWi’s defenses for failure to comply with local rules.

Megace ES is a drug used for treating anorexia, cachexia, and unexplained weight loss in patients with HIV and AIDS. Megace ES constitutes an improvement over its predecessor, Megace OS, which was best absorbed on a full stomach.  Megace ES absorption levels tend to be constant, regardless as to whether the patient takes it on a full or empty stomach. This is particularly advantageous because the targeted patient population often suffers from weak appetite.

The court denied TWi’s motion for summary judgment, and granted Par’s cross-motion for partial summary judgment.

Why Par Prevailed:  The court first construed two disputed claim terms: “single administration” and “no substantial difference.” TWi argued that “single administration” made no sense because it referred to both a fed and fasted blood level. The court found TWi’s argument unconvincing. The intrinsic evidence supported the claim language disclosing the superior ability of the new drug to be taken with or without food. The court also noted that the claim term, found in a wherein clause, was immediately preceded by a description of the drug being taken once daily. The court concluded that the claim did not need to be re-drafted, and that when the term was interpreted in light of the entire patent, it could be easily understood.

Next, TWi argued that the term “no substantial difference” should be construed to mean “bioequivalent” under FDA guidance concerning food effects. The claim at issue required that there be “no substantial difference” in the Cmax when the drug was administered to the patient in a fed or fasted state. The TWi-referenced FDA guidance defined bioequivalent as “80-125% of the comparator.” The court disagreed with TWi’s interpretation, finding that it had grossly oversimplified the FDA guidance. The court also found that relying upon extrinsic evidence such as FDA guidelines was unnecessary when the intrinsic evidence adequately informed a skilled artisan of the meaning of the disputed claim term. The court also noted that the meaning of the term, when one considered that the Cmax of Megace OS had a fed/fasted variation of about 700%, compared with Megace ES, which had a fed/fasted Cmax variation of 7-84%, was abundantly clear. Last, the court relied on TWi’s own proposed label for its generic product, which indicated it could be taken “without regard to meals.”

The court next addressed TWi’s non-infringement arguments. TWi argued that it was not a direct infringer of the ’576 patent because TWi does not treat patients. In response, Par argued that it was not claiming infringement under § 271(a). The court, however, found that the complaint was broad enough to include a direct infringement claim, and agreed with TWi that such a claim had no merit. TWi next argued that its ANDA drug did not infringe claim 1 because it showed a 29% Cmax difference based on the food effect. This argument was based on TWi’s proposed construction incorporating the FDA guidelines. Under the Court’s adopted construction, which rejected TWi’s arguments concerning the FDA guidelines, there was a genuine issue of material fact as to whether TWi’s generic would infringe the claim. TWi next argued that it could not infringe claim 4, a Markush claim. Specifically, TWi argued that it could not infringe because its ANDA drug met the claim limitation under multiple members of the claimed Markush group. The court found that TWi had misinterpreted Federal Circuit caselaw on the issue. The Federal Circuit never held that multiple members of a Markush group could not exist simultaneously in an invention, only that one and only one member could be used to satisfy a claim. The court held that because TWi’s ANDA drug may infringe multiple members of claim 4’s Markush group, summary judgment of non-infringement was denied.

Next, the court addressed the issue of invalidity.  First, TWi alleged that Par was collaterally estopped from asserting the ’576 patent based on a BPAI decision on an application that was “related” to the ’576 patent. The court disagreed for three reasons: (i) TWi faced a heavier burden of persuasion here (clear and convincing) than Par faced before the USPTO (preponderance of the evidence); (ii) TWi admitted that the fed/fasted claim limitation was not addressed in the prior proceeding; and (iii) TWi failed to cite any authority that issues in a one-party BPAI proceeding should be given preclusive effect and applied against another party in district court litigation.

Next, TWi argued that the Markush group in claim 4, which references Cmax, did not meet the written description requirement because the specification only referred to Tmax and AUC (total absorption).  The court rejected this argument because Tmax, Cmax and AUC are all mathematically related, and are calculated in reference to each other. While the claim may have been poorly drafted, summary judgment for lack of written description was not proper.

Concerning anticipation, TWi argued that the ’576 patent was anticipated by the ’363 patent. The examiner had cited the ’363 patent during the prosecution of the ‘576 patent. Additionally, the ’363 patent disclosed anti-cancer agents instead of treatments for HIV/AIDS-related disorders. The ’363 patent also did not claim a treatment for weight loss. Most importantly, the ’363 patent made no mention of the lack of a food effect, which was the central innovation of the ’576 patent. The court therefore granted Par’s motion for summary judgment.

Concerning obviousness, TWi argued that a Megace OS monograph, in combination with an unrelated patent application filed in 2002 that sought to patent a megestrol-related drug, rendered the ‘576 patent obvious.  Par responded that the references only involved Megace OS-sized particles (larger than Megace ES) and that the references also failed to address the food effect that was the central innovation of the ’576 patent.  Because there were too many underlying factual issues to resolve the question on summary judgment, TWi’s motion for summary judgment was denied.

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