A Delaware patent infringement case has erupted into an antitrust dispute, after an India-based generic drugmaker accused Mylan Pharmaceuticals of using its lawsuit to stifle competition for its topical foam acne treatment.

Glenmark Pharmaceuticals on Monday urged a federal judge in Wilmington to greenlight its counterclaims that Mylan had filed “sham litigation” in order to delay approval of a generic version of Evoclin, which is used to treat acne in teenagers and adults.

The lawsuit, Glenmark said in a court filing, was designed to trigger an automatic stay under the Hatch-Waxman Act that would keep Glenmark's product off the market for at least 30 months, while the infringement case is litigated.

“Mylan's infringement action is both objectively and subjectively baseless and, for purposes of this motion, undisputably motivated by anticompetitive intent,” attorneys for Mumbai, India-based Glenmark and its American subsidiary said.

Mylan, whose global headquarters is in Canonsburg, Pennsylvania, sued Glenmark for infringement in November. It has refuted Glenmark's monopolization claim in court filings as a “hurriedly cobbled together set of conclusory allegations which must be dismissed.”

A spokeswoman for Mylan was not immediately available to comment on Tuesday.

In its Nov. 15 complaint, Mylan said that Glenmark's planned generic infringed two patents covering clindamycin phosphate, Evoclin's active ingredient.

Glenmark, however, responded that its product does not include a base, which is required by each of Mylan's patents in order to balance Evoclin's pH levels without upsetting the active ingredient. The company argued that Mylan was aware of the differences between the two treatments, but pushed ahead with its infringement suit anyway in an attempt to maintain its grip on the market for treatment with topical clindamycin foam.

Mylan asked U.S. District Judge Richard G. Andrews of the District of Delaware to dismiss the monopolization counterclaim last month, saying there was nothing to support the “bald assertion” that its acne treatment constituted a market unto itself.

On Monday, Glenmark stood by its reasoning that Mylan had the power to control prices and exclude competition, arguing that Evoclin lacked any directly competitive companies trying to sell an identical product.

“While other forms of topical clindamycin products are available on the market—in the form of gels, lotions and solutions—the '237 and '747 patents disclose that foam products offer advantages particularly relevant to the treatment of acne,” the company said.

In addition to the antitrust claim, Glenmark has argued that Mylan's patents are invalid and cannot be infringed.

The case, filed in the U.S. District Court for the District of Delaware, is captioned Delcor v. Glenmark Pharmaceuticals.

Mylan is represented by David E. Moore, Bindu Ann Palapura and Stephanie E. O'Byrne of Potter Anderson & Corroon and Alissa M. Pacchioli, Deepro R. Mukerjee, Derek S. Neilson, Jitendra Malik, Joseph M. Janusz, Lance Soderstrom and Stephanie M. Roberts of Alston & Bird.

Glenmark is represented by Claire A. Fundakowski, Kathleen B. Barry and Maureen L. Rurka of Winston & Strawn and Dominick T. Gattuso of Heyman Enerio Gattuso & Hirzel.