Sanofi, Regeneron sue Amgen to protect eczema drug from patent claims

Boston : Sanofi SA and Regeneron Pharmaceuticals Inc filed a lawsuit seeking a court order declaring that their eczema drug Dupixent, awaiting a U.S. approval decision, does not infringe an Amgen Inc patent for a failed asthma treatment.

The lawsuit, filed in federal court in Boston, was intended to preempt one expected to be brought by Amgen, which has previously sued Sanofi and Regeneron over their rival cholesterol drug Praluent.

"Sanofi and Regeneron wish to eliminate any potential obstacle Amgen might seek to raise against the planned U.S. commercialization of Dupixent," the plaintiffs said in the lawsuit.

The suit came two months after a federal judge in Delaware blocked Sanofi and Regeneron from selling Praluent because it was found to infringe Amgen's Repatha patent. Praluent was allowed to remain on the market during the appeals process.

Sanofi and Regeneron argue they have spent hundreds of millions of dollars developing Dupixent, which earned breakthrough therapy designation from the U.S. Food and Drug Administration.

The injectable drug, known chemically as dupilumab, is seen as a critically important future growth driver for both companies, with annual sales forecast to exceed $5 billion by 2023, according to Thomson Reuters data.

The companies have called Dupixent a "game-changer" in moderate-to-severe atopic dermatitis, a type of eczema that causes extreme itching. The lawsuit said plans were underway to begin selling Dupixent as soon as it wins FDA approval, a decision due next week.

The patent at issue in the lawsuit was issued to Amgen in the 2000s, when it was attempting to develop an asthma treatment. Amgen abandoned development of the drug following disappointing results, the lawsuit said.

The complaint said in recent days lawyers for Sanofi and Regeneron learned Amgen had hired lawyers to pursue patent infringement litigation related to Amgen's work on that treatment. Dupilumab is also being tested for asthma and other indications.

"We took this proactive step to protect the value of our innovative therapy Dupixent and ensure access of this important medicine for physicians and patients," Sanofi said in a statement, adding that it seeks a court declaration that its development, manufacturing, sale, promotion and related activities for Dupixent do not infringe a patent held by Amgen.

Amgen did not immediately respond to requests for comment.

The case is Sanofi-Aventis U.S. LLC et al v. Amgen Inc et al, U.S. District Court, District of Massachusetts, No. 17-cv-10465.