Regeneron, Sanofi urge court to reverse ban on cholesterol drug

June 6 (Reuters) - A federal appeals court hinted on Tuesday it may let Sanofi AG and Regeneron Pharmaceuticals Inc sell a cholesterol drug Amgen Inc has been trying to block on patent infringement grounds, according to lawyers and analysts who attended oral arguments in the case.

Paul Clement, a lawyer for Regeneron and Sanofi, urged the U.S. Court of Appeals for the Federal Circuit to reverse a lower court order that would ban sales of their jointly developed drug Praluent for 12 years because it infringed patents owned by Amgen Inc, which makes a competing drug, Repatha.

Clement asked the court to invalidate Amgen’s patents because they improperly claim a broad monopoly on an entire category of antibodies, known as PCSK9 inhibitors, that lower “bad” cholesterol levels.

Amgen’s lawyer, Daryl Joseffer, argued the injunction was the only fair outcome in the dispute after a jury upheld the validity of Amgen’s patents. He also said Amgen’s patents reflect true innovations that resulted from a $2 billion investment in research and development.

Zachary Silbersher, a patent lawyer at Kroub, Silbersher & Kolmykov who is not involved in the case, said the three judges’ questions frequently put Jossefer on the defensive and suggest that they may be “leaning a little toward Regeneron.”

Silbersher noted that much of the argument focused on whether the trial judge unfairly handicapped Regeneron and Sanofi by blocking them from presenting certain evidence during the jury trial. That line of questioning suggests the Federal Circuit could order a do-over trial in the case, he said.

Umer Raffat, an analyst at the investment banking advisory firm Evercore ISI, agreed the case is “leaning more toward Regeneron” but added that it was “impossible to call with high conviction.”

PCSK9 inhibitors like Repatha and Praluent have been shown to dramatically lower “bad” LDL cholesterol and are expected to generate billions in sales. The U.S. Food and Drug Administration approved both drugs in 2015.

Amgen sued Paris-based Sanofi and Tarrytown, New York-based Regeneron in 2014. A federal jury in Delaware upheld the validity of Amgen’s patents in March 2016, prompting U.S. District Judge Sue Robinson to hand down an injunction blocking Praluent sales for 12 years.

The sales ban was stayed pending Regeneron and Sanofi’s appeal. (Reporting by Jan Wolfe; Editing by Dan Grebler)