A Delaware federal judge has barred Amneal Pharmaceuticals from marketing a generic version of Galderma Laboratories' Oracea acne drug through 2025, finding that the drug infringed under the equitable doctrine of equivalents.

The Aug. 27 opinion from U.S. District Chief Judge Leonard P. Stark of the District of Delaware, made public on Aug. 31, followed a five-day bench trial in February and capped Galderma's 18-month effort in the U.S. District Court for the District of Delaware to protect Oracea, which generates sales of nearly $300 million per year.

In the 88-page redacted ruling, Stark said that Amneal's planned product infringed five patents for Galderma's once-daily treatment for acne rosacea, a skin disorder known to cause redness and small, pus-filled bumps.

An attorney for Galderma said Tuesday that the ruling was notable because it found Amneal's generic had infringed under the doctrine of equivalents and not under the more common theory of literal infringement. According to court documents, Galderma had raised arguments for literal infringement before trial, but Stark struck the contentions because they were raised too late in the case.

However, Stark found by a preponderance of evidence that Amneal's product was “insufficiently different” from Oracea, even though it did not fit the literal scope of Galderma's patents.

“We're extremely gratified by the court's decision protecting Galderma's critical patent rights,” said Gerald J. Flattmann, a partner in King & Spalding's New York offices, who represented the Texas-based company. “This was a classic case where the equitable doctrine of equivalents applied.”

In a joint status report filed last week, both sides agreed that no further proceedings were needed in the district court case. An attorney for Amneal did not respond to a call Tuesday seeking comment on the ruling and the company's plans to appeal.

In his opinion, Stark said Amneal's planned bioequivalent infringed claims for three sets of Galderma patents, including one that described chemical compositions for the “delayed release” of Oracea's active ingredient, doxycycline.

Despite “strong evidence on both sides,” Stark rejected Amneal's argument that the release of doxycycline was not delayed with its generic, and he rebuffed the defendant's warnings that Galderma's position sought to upend the difference between am immediate release and a delayed one.

“While Amneal's argument that, under Galderma's theory, an otherwise purely [immediate release] formulation could be considered to have a [delayed release] portion (that is, the innermost molecules of the [immediate release] portion) is clever, it does not justify judgment for Amneal,” he said. “Simply put, Amneal's hypothetical product is not before the court.”

For King & Spalding the case was not the first time it had secured a victory in protecting Oracea from generic competition. In 2011, the firm successfully litigated a challenge to a comparable Mylan generic all the way through trial. Flattmann said the firm had secured a similar result involving a Dr. Reddy's generic before the Patent Trial and Appeal Board, and Amneal also dropped plans for another drug amid pushback from Galderma.

“This is the fourth or fifth time that we've been able to successfully defend the patent protections for Oracea,” Flattmann said.

As of Tuesday afternoon, Amneal had not yet filed a notice of appeal.

Galderma was represented by Flattmann, Evan Diamond and Vanessa Yen of King & Spalding and Jack B. Blumenfeld of Morris, Nichols, Arsht & Tunnell.

Amneal was represented by George C. Lombardi, Maureen L. Rurka, Kevin E. Warner, Karalena M. Guerrieri, Ryan B. Hauer and Elizabeth E. Grden in Winston & Strawn's Chicago office and Eimeric Reig-Plessis in the firm's Washnington, D.C., office. Anne Shea Gaza and Samantha G. Wilson of Young Conaway Stargatt & Taylor acted as local counsel.

The case was captioned Galderma v. Amneal.