Dive Brief:

• A federal jury on Monday upheld the validity of two patents held by Amgen on antibodies that work similarly to its cholesterol drug Repatha, setting back the rival team of Sanofi and Regeneron for the second time in a long-running court fight.
• While jurors in the case affirmed three of the five claims asserted by Amgen through the two patents, the verdict does not currently impact the U.S. availability of Sanofi and Regeneron's drug Praluent, which competes with Repatha.
• Begun in 2014, the simmering legal fight between the two camps looks likely to continue further still. Sanofi and Regeneron said they intend to file post-trial motions in the coming months in an effort to overturn the verdict and request a new trial. 

Dive Insight:

Approved to blockbuster sales expectations more than three years ago, Repatha (evolocumab) and Praluent (alirocumab) have been jockeying for competitive positioning since. 

Both work by blocking binding between proprotein convertase subtilisin/kexin type 9, or PCSK9 and the LDL cholesterol receptor, thereby freeing LDL receptors to clear LDL cholesterol instead. The drugs potently lower LDL cholesterol, conferring heart benefits to adult patients with established cardiovascular disease. 

Despite clinical profiles that include positive cardiovascular outcomes data, Repatha and Praluent have widely fallen short of expectations, competing for a market much less lucrative than once thought. Only last quarter did sales of the two drugs together surpass an annualized billion dollar run rate. 

Even so, a protracted legal battle between Amgen and the Sanofi and Regeneron team continues. 

Amgen actually won a previous district court verdict in March 2016, resulting in federal judge Sue Robinson granting ten months later a short-lived injunction against sales of Praluent in the U.S. 

Sanofi and Regeneron promptly appealed, successfully taking the case to the U.S. Court of Appeals for the Federal Circuit and obtaining a partial reversal that remanded the case to the Delaware district court. 

Now, the parties look set to begin that process again, although this time proceedings could move faster, wrote Mizuho analyst Salim Syed in an investor note. 

In addition to requesting a new trial, Sanofi and Regeneron indicated they were prepared to appeal again to the U.S. appeals court. 

“It is our longstanding belief that all of Amgen's asserted U.S. patent claims are invalid and we believe the law and the facts support our positions," said Sanofi and Regeneron in a joint Feb. 25 statement. 

The Delaware district court will hold an injunction hearing in June this year, and Amgen plans to seek a permanent injunction on Praluent sales, Syed said. 

Still, procedural steps from Regeneron could drag the process on for longer, too. 

"What's clear is that this back-and-forth is going to continue in the background for some time," wrote Piper Jaffray analyst Christopher Raymond in a Feb. 25 note to investors.