January 23, 2017
Case Name: Aptalis Pharamtech, Inc. v. Apotex Inc., Civ. No. 14-1038-SLR, 2016 U.S. Dist. LEXIS 169520 (D. Del. Dec. 8, 2016) (Robinson, J.)
Drug Product and U.S. Patent: Amrix® (cyclobenzaprine); U.S. Patents Nos. 7,790,199 (“the ’199 patent”) and 7,829,121 (“the ’121 patent”)
Nature of the Case and Issue(s) Presented: The common specification of the patents-in-suit is directed to oral formulations of the skeletal muscle relaxant drug cyclobenzaprine having extended release coatings. Defendants’ ANDA products consist of a matrix system containing a water-insoluble polymer used to provide extended release of cyclobenzaprine. The only issue at trial was whether defendants’ extended-release cyclobenzaprine products met the single disputed claim limitation: “extended release coating comprising a water insoluble polymer membrane surrounding” the active ingredient particles. The court held that the claim term covered the matrix system in Defendants’ ANDA and found that those products would infringe the patents-in-suit.
Why Aptalis Prevailed: The parties agreed that the exterior surface of defendants’ ANDA product does not have an extended-release coating. The infringement inquiry thus focused on whether the interior the product satisfied the disputed limitation. Plaintiffs’ expert presented eight SEM and eight corresponding EDS images of a fractured mini-tablet produced by defendants. He identified a drug particle surrounded by polymer in a SEM image. He further testified that he did not rely on the EDS images in his infringement analysis. Defendants’ expert opined that the SEM images did not allow unequivocal distinguishing between drug particles, polymer particles, and other particles. Defendants’ expert concluded that “there [are] no drug particles surrounding polymer particles, and there [are] no polymer particles ... surrounding drug particles.”
Plaintiffs’ expert also explained that there are many methods to make extended-release drugs to “slow down the contact between gastrointestinal fluids and drug,” thereby slowing “down the drug being released.” Dr. Muzzio walked through defendants’ manufacturing method, explaining that the formulation of polymer and cyclobenzaprine forms a “sticky” mixture, which is then compressed and tableted. He concluded that the structure of defendants’ ANDA product is “drug particles ... embedded in a matrix that is predominantly polymer.” As to the term “surrounding,” he explained that the polymer “covers a significant fraction of the drug particle surface, and the probability of the matrix being present in any location around the perimeters is more or less the same. So in the average situation, there will be matrix material at different places around each drug particle.”
Defendants’ expert characterized the patent as describing a “membrane system” and defendants’ product as a “matrix system.” He opined that defendants’ manufacturing process resulted in “a matrix extended release system, which has no coating and no layer,” and that a POSA would not characterize the polymer particles in defendants’ products as a coating or as forming a layer. He further explained that the court’s construction provides that the layer of substance be “applied onto” the surface of another, which defendants’ manufacturing process does not do. In his opinion, a POSA would just as easily characterize the matrix system of defendants' tablets as layering drug particles onto the polymer particles versus layering polymer particles onto the drug particles.
The court did not find the SEM/EDS analyses particularly helpful. Plaintiffs’ expert’s explanations and conclusions regarding defendants’ manufacturing process, on the other hand, were reasonable and consistent with the disputed claim limitations as construed by the parties and the court. The court found that the drug particles are embedded in sufficient polymer particles for the resulting formulation to be described as drug particles “covered by” or “surrounded” by polymer particles.
