IP Law Daily Generic drug maker’s transdermal patch adhesive substantially similar to patent claims
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Tuesday, June 25, 2019

Generic drug maker’s transdermal patch adhesive substantially similar to patent claims

By John W. Scanlan, J.D.

An adhesive in a generic drug manufacturer’s accused transdermal patch was substantially similar to the adhesives in the asserted claims, and the manufacturer did not dispute that its products met every other element of the claims.

Generic transdermal patches for administrating a drug to treat Parkinson’s diseases infringed UCB’s patent under the doctrine of equivalents, the U.S. Court of Appeals for the Federal Circuit held in affirming a district court’s ruling finding infringement and upholding the validity of the patent. However, the court invalidated the challenged claims of a related patent under the public use bar because the evidence showed that the relevant product had been used by at least one patient before the patent application was filed (UCB, Inc. v. Watson Laboratories Inc., June 24, 2019, Chen, R.).

UCB, Inc., UCB Manufacturing Ireland Limited, UCB Pharma GmbH, and LTS Lohman Therapie-Systeme AG (together, "UCB") own two patents related to the transdermal administration of rotigotine, a dopamine receptor stimulator used to treat Parkinson’s disease: U.S. Patents No. 6,884,434 (the ’434 patent) and 8,232,414 (the ’414 patent). The ’434 patent involved the development of a transdermal patch that delivers rotigotine without the use of water. UCB has sold this patch under the Neupro brand name since July 2007. After UCB discovered in August 2007 a polymorph form of rotigotine had precipitated during manufacture, it filed a patent application (for the ’414 patent) for the newly discovered form of crystalline rotigotine, and also notified the FDA that crystalline rotigotine had been discovered on already-distributed batches of rotigotine.

Actavis filed an Abbreviated New Drug Application (ANDA) for generic transdermal rotigotine patches, which it called PIB Neupro as it substituted polyisobutylene-based adhesive for the silicone-based adhesive used by UCB. UCB brought patent infringement claims, and Actavis challenged the validity of certain claims in UCB’s patents. The district court found in favor of UCB on the infringement claims and upheld the challenged claims of the ’434 patent but invalidated the challenged claims of the ’414 patent on the ground that at least one patient had used Neupro patches with crystalline rotigotine before the priority date. Actavis appealed the infringement and validity rulings regarding the ’434 patent but stipulated to infringement of the ’414 patent. UCB cross-appealed the invalidation of the ’414 patent.

Doctrine of equivalents/limitations. The Federal Circuit first determined that prosecution history estoppel did not prevent UCB from asserting infringement under the doctrine of equivalents because the examiner’s issuance of a restriction requirement directing UCB to choose between prosecuting two sets of claims did not relate to polyisobutylene and the examiner was not communicating anything about the patentability of polyisobutylene adhesive systems. Furthermore, there was not enough in the specification, claims, or record evidence of the inventor’s knowledge for the court to conclude that UCB had surrendered polyisobutylene as a possible equivalent. The court observed that inventors should not be required to delay filing for patents while testing for all known possible equivalents or be incentivized to claim equivalents they had not tested. The district court’s finding that polyisobutylene was an equivalent did not vitiate the "acrylate-based or silicone-based" claim language because that finding did not cover all adhesive systems. Finally, Actavis did not offer any examples of prior art that would be ensnared by the addition of polyisobutylene to the claim.

Doctrine of equivalents/substantial similarity. Noting that Actavis did not dispute that PIB Neupro met every other element of the asserted claims, the Federal Circuit upheld the district court’s finding that Actavis infringed the ’434 patent based upon the doctrine of equivalents, stating that the polyisobutylene-based adhesive used by Actavis was substantially similar to the acrylate-based or silicone-based polymer adhesives claimed by UCB. It found no clear error in the district court’s findings that polyisobutylene, silicates, and acrylates had certain properties in common, nor in its findings that a skilled person in the art would recognize that polyisobutylene-based adhesives were not substantially different from the silicon-based or acrylate-based adhesives within the scope of the claims. The district court also found that while there were some differences, test results showed that these differences did not affect how the claimed invention worked. The court determined that the polyisobutylene-based adhesive system was an "insubstantial modification" of the invention.

Actavis argued that the district court erred in finding equivalence because Neupro contains water and, therefore, was not equivalent to the patent claims that cite free base rotigotine in the absence of water. However, whether Neupro was an embodiment of the claims was not dispositive because the issue involved a comparison of the accused product to the claims. The district court relied upon evidence comparing Neupro and PIB Neupro only for points unrelated to water content, and it was unclear to the Federal Circuit how any of these conclusions were affected by Neupro’s water content.

Anticipation, obviousness. The Federal Circuit agreed that the ’434 patent was not invalid for anticipation by a prior art patent application by Cygnus Therapeutic Systems, which listed rotigotine as an exemplary drug. Actavis did not present sufficient evidence that rotigotine free base was present in a patch that is water-free, as in UCB’s claims—all of Cygnus’ examples contain significant amounts of water. It upheld the district court’s rejection of Actavis’ argument that the asserted claims would have been obvious in light of the patch recipe of Miranda (an international patent for a transdermal device) combined with the rotigotine free base of Timmerman (a journal article) because Actavis did not provide an adequate rationale for combining the teachings of those references. Considering the list of thousands of possible combinations disclosed by Miranda in making transdermal patches, a skilled artisan would not have had a reasonable expectation of success in combining them, even if motivated.

Prior public use. Finally, the Federal Circuit upheld the invalidation of the asserted ’414 patent claims due to prior public use under Sec. 102(a). Two days after the priority date of the patent, a patient experienced an adverse effect while being treated with Neupro that contained crystalline rotigotine. Evidence showed that most if not all the patches from the same lot as that patient’s patches contained crystalline rotigotine; the patient had not experienced the adverse effect from earlier lots and her condition improved as she began using different patches. As she had been using patches from this lot for a week, it was reasonable for the district court to find that she had been using the crystalline rotigotine prior to the patent’s filing date two days earlier and, thus, the ’414 patent was invalid for prior public use. Although UCB argued that these patches did not count as "use" pursuant to Sec. 102 because the crystalline rotigotine cannot penetrate the skin and, therefore, had no therapeutic function, the asserted claims covered crystalline rotigotine without any limitations as to use.

This case is Nos. 2018-1397 and 2018-1453.

Attorneys: James Trainor (Fenwick & West LLP) and Jack B. Blumenfeld (Morris, Nichols, Arsht & Tunnell LLP) for UCB, Inc., UCB Manufacturing Ireland Ltd., UCB Pharma GmbH and LTS Lohmann Therapie-Systeme AG. John C. O'Quinn (Kirkland & Ellis LLP) for Watson Laboratories Inc. and Actavis Laboratories UT, Inc.

Companies: UCB, Inc.; UCB Manufacturing Ireland Ltd.; UCB Pharma GmbH; LTS Lohmann Therapie-Systeme AG; Watson Laboratories Inc.; Actavis Laboratories UT, Inc.

MainStory: TopStory Patent FedCirNews

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