Sanofi, Regeneron avoid Praluent disaster as appeals court stays injunction in PCSK9 patent case

Regeneron and Sanofi won’t have to pull Praluent off the market after all—at least not yet. A U.S. appeals court on Wednesday decided to let the PCSK9 cholesterol drug remain on pharmacy shelves while it sorts out an appeal in a patent fight with Amgen, which makes a rival drug.

It was a dramatic reversal in a hard-fought argument over the injunction—one that some analysts doubted the Praluent partners could win. The stay is a big deal for Praluent, which would have lost ground, perhaps forever, in its fight for market share against Amgen’s drug. It’s also a big deal for Repatha; after U.S. District Judge Sue Robinson granted Amgen’s request for an injunction, some analysts amped up their expectations for Repatha sales this year, should the injunction stick.

In fact, there's evidence that Repatha was already benefiting from the patent fight, according to one analyst. For the week of Jan. 20, Repatha’s prescription total hit 3,231, ahead of Praluent’s 2,859, Bernstein analyst Ronny Gal reported in a note last week. The 53%-to-47% ratio was the largest weekly gap since the middle of last year, the analyst wrote.

“This should not be surprising,” he wrote. “As payers (and sometimes physicians) begin to consider the risk of Praluent removal from the market, they not surprisingly begin to prefer the safer option.”

Here's the background: Amgen, Repatha and its PCSK9 patents had prevailed in a trial court verdict last year, and the California biotech then won an injunction to block Praluent sales. Robinson batted aside Sanofi and Regeneron’s first attempt to postpone that injunction pending appeal, but the Federal Circuit Court of Appeals has now granted their request for a stay.

The latest court ruling is no guarantee that Sanofi and Regeneron will win in the end. It merely allows their drug to remain on sale while the Circuit Court weighs the two sides’ arguments in the patent appeal. But as Barclays analysts pointed out in a Wednesday note, the appeals panel cited the merits of the underlying case as one of two key reasons why it gave Praluent its reprieve.

"The first reason for granting the appeal is most telling in that the Appeals Court believes the case presented by Sanofi/Regeneron demonstrates a strong likelihood that Amgen’s patents could be found invalid," Barclays analyst Geoff Meacham wrote in the note.

Regeneron CEO Len Schleifer essentially said the same thing during the company's Thursday earnings call. "Our opening brief on the underlying appeal, … that’s what they’re talking about. We’re going to now go try and win on the merits."

Amgen, for its part, said in a statement that it respects the court’s decision, but “remains confident in the validity of our patents and the correctness of the jury verdict and district court’s judgment. We look forward to presenting our case on the lack of merit in Defendants’ appeal.”

Sanofi said via email that it’s “pleased” that the appeals court stayed the injunction for Praluent, “giving patients in the U.S. continued access to this important medicine during the appeal process. It is our longstanding position that Amgen’s asserted patent claims are invalid.”

Word Wednesday afternoon was the appeals court had set up an expedited schedule for the case, with a ruling expected in as little as four months, or as long as 10.

Right now, there’s not much of a market to fight over. Praluent and Repatha launched within a month of each other, and the competition between the two has been fierce. The two drugs have each racked up exclusive deals with some payers, though some top payers are covering both.

Even so, PCSK9 sales are still faltering, because patients often have to clear prior authorization hurdles to get their prescriptions covered. That's partly because the drugs both carry list prices of $14,000 or more, and, until Amgen's top-line data release from Repatha's outcomes trial, no proof yet that the drugs actually prevent heart attacks, strokes and the like—though they are immensely effective at lowering "bad" LDL cholesterol.

Amgen is set to unveil details of Repatha's outcomes trial at the American College of Cardiology meeting next month; the Praluent data won't be in until late this year. But in any case, Sanofi and Regeneron now know they can remain in the fight, at least until the Circuit Court hands down its decision.