Case Name: Almirall, LLC v. Torrent Pharms., Ltd., Civ. No. 20-1373-LPS (D. Del. July 13, 2021) (Stark, J.) 

Drug Product and Patent(s)-in-Suit: Aczone® Gel, 7.5% (Dapsone); U.S. Patent No. 9,517,219 (“the ’219 patent”)

Nature of Case and Issue(s) Presented: In August 2020, Torrent sent a notice letter to Almirall regarding the submission of Torrent’s ANDA to FDA for permission to market a generic version for Almirall’s Aczone Gel. Torrent’s ANDA contained a “Paragraph IV” certification that the ’219 patent was invalid and/or not infringed by Torrent’s ANDA product. Almirall sued Torrent under 35 U.S.C. § 271(e), alleging that Torrent’s proposed ANDA product infringed the ’291 patent. After the pleadings closed, Torrent filed a motion for judgment on the pleadings on its counterclaim of non-infringement. It argued that its proposed formulation could not literally infringe because it did not contain an ingredient required by the claims of the ’291 patent, and it did not infringe under the doctrine of equivalents because the doctrine of argument-based prosecution history estoppel applied. The court agreed with Torrent and granted its motion for judgment of non-infringement on the pleadings.

Why Torrent Prevailed: The ’219 patent claims required the pharmaceutical compositions to have “a polymeric viscosity builder comprising acrylamide/sodium acryloyldimethyl taurate copolymer” (“A/SA”). But Torrent’s proposed formulation did not contain A/SA. Instead, Torrent's ANDA product contained carbomer homopolymer type C, also known as “Carbopol.” Almirall apparently conceded that there was no literal infringement, but proceeded on a theory of infringement under the doctrine of equivalents.

Torrent argued that Almirall surrendered Carbopol as an equivalent to A/SA during prosecution and therefore was barred from asserting equivalents under the doctrine of argument-based prosecution history estoppel. The court explained, “[a]rgument-based prosecution history estoppel bars a patent owner from asserting equivalents for a claim element when that assertion would contradict statements made to the patent examiner in the course of obtaining the patent.”

Here, the court determined that Almirall “clearly and unmistakably” surrendered Carbopol as an equivalent to A/SA when it argued the following during prosecution of a parent patent:

The instant claims recite a new formulation of dapsone wherein the active ingredient is about 7.5% w/w dapsone and an entirely new thickening agent is employed. The new formulation of the instant claims does not include a carbomer such as Carbopol®, but instead utilizes as [sic] acrylamidelsodium acryloyldimethyl taurate copolymer, also known as “Sepineo™ P 600,” and at a much higher concentration (about 2% to about 6% w/w) as compared to what Garrett teaches for its thickening agent.

The court explained that it was appropriate to consider the prosecution history of the parent patent because the disputed claim elements were nearly identical in both patents and because during prosecution of the ’219 patent, the application expressly adopted the arguments made during prosecution of the parent patent and expressly repeated the argument above. Moreover, the applicant referred to A/SA as the “sole thickener” or “sole thickening agent” several times. In holding that these statements met the high bar of “clear and unmistakable” surrender of Carbopol as an equivalent to A/SA, the court stated “[i]t is difficult to imagine a clearer disclaimer of Carbopol than ‘[t]he new formulation of the instant claims does not include a carbomer such as Carbopol.” Almirall was not able to offer any persuasive argument that the above statements meant anything other than what the words plainly said. Instead, Almirall merely contended that it was entitled to discovery before the court entered judgment. The court disagreed, stating that Almirall had not made a plausible allegation of infringement and therefore was not entitled to discovery.

Almirall argued that the court should deny the motion because another judge in the District of Delaware denied a similar Rule 12(c) motion by a different generic pharmaceutical company in a case involving the same NDA for Aczone Gel. The court declined because: (i) courts have discretion to deny Rule 12(c) motions; and (ii) the facts of the other case were not as straightforward—the generic filer used a “multi-component polymeric viscosity builder” in its proposed formulation, and therefore the infringement case presented more difficult questions that would benefit from fact and expert discovery.

DISCLAIMER: Because of the generality of this update, the information provided herein may not be applicable in all situations and should not be acted upon without specific legal advice based on particular situations.

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