Is Praluent doomed? Regeneron, Sanofi appeal for a reprieve, but experts are skeptical

Sanofi and Regeneron have made their bid for a Praluent reprieve. In the wake of a district judge’s patent ruling that could push the partners’ new cholesterol drug off the market, the two companies are asking the Federal Circuit Court to delay long enough to hear their appeal in the case.

Earlier this month, U.S. District Judge Sue Wilson granted rival drugmaker Amgen’s request for an injunction blocking Praluent from the market. The two drugs work to dramatically lower “bad” LDL cholesterol by inhibiting the PCSK9 protein, and Amgen claims that Praluent steps on its PCSK9 patents.

Before that injunction was granted, Sanofi and Regeneron had been expected to strike a royalties deal with Amgen, giving the Big Biotech a share of their Praluent yield. But now, analysts are discounting the prospect of a settlement. In less than 45 days, Amgen’s Repatha could have the PCSK9 market all to itself—and analysts say that would give Amgen the power to negotiate better prices with payers, in addition to capturing every PCSK9 prescription. 

If Sanofi and Regeneron’s appeal doesn’t succeed, that is. In addition to appealing the lower court’s decision validating Amgen’s patents, the two companies are asking the Federal Circuit to postpone the date the injunction takes effect long enough for their appeal to be heard.

And there again, some experts are skeptical. In a Friday note, Leerink Partners analyst Geoffrey Porges said that the firm’s patent specialists were “quite pessimistic” about the partners’ prospects for extending the stay of the injunction past the current 45 days. 

The upshot of that? “[R]egardless of the ultimate merits of Regeneron and Sanofi’s case, they will face an unprecedented (and probably first) branded pharmaceutical product withdrawal in the middle of this quarter,” Porges said.

Perhaps the closest parallel would be another Amgen case, when it sued Roche to block Mircera, a would-be competitor to its anemia drug Epogen. In 2009, Amgen won an injunction against that drug’s launch, and it was forced to stay off the market until the disputed patent expired.

The Praluent partners are pushing for a longer stay of the injunction that would require them to pull the drug from the market, arguing that the loss of Praluent as a Repatha alternative is not in the public interest. More than 100,000 patients are taking Praluent now, and switching could be problematic for those now taking the lower dose.

Analysts say the Federal Circuit tends to side with the patent holder, and in the past hasn’t turned a favorable eye on arguments that removing a healthcare product from the market would hurt the public. In fact, several medical devices have suffered the same fate that Praluent faces.

Jefferies analysts, for one, are so skeptical of a Sanofi/Regeneron victory that they’re discounting Praluent entirely. “As a result of the ruling, we are removing all value from Praluent starting in 2018,” Jefferies analysts wrote after the injunction was granted.

As for Regeneron and Sanofi’s patent appeal itself, the two companies repeat their argument that Amgen’s patents are too broad, claiming ownership of a “genus” of antibodies for PCSK9, and, simultaneously, that the patents only specify two particular antibodies, Repatha and another “with a structure entirely different from Praluent.” They also claim that the lower-court judge was “struggling” with the issues raised in the case—and that Wilson’s decision to grant the injunction was in itself contradictory.

“[T]he district court granted Amgen’s extraordinary request to take Praluent off the market, even though the court found that the public interest weighed against an injunction,” the appeal states, going on to add, “This is a textbook case for a stay pending appeal.”

Amgen of course disagrees, and last week sent out a statement defending its bid for an injunction. Its rivals knew about Amgen’s intellectual property “long before the lawsuit was filed” and eventually admitted infringment of its PCSK9 patents, Amgen said.

“Sanofi and Regeneron chose to launch a product that they had no right to manufacture or sell, [and] ... were afforded a full and fair opportunity to challenge the validity of Amgen’s patents at trial and the jury determined our patents to be valid. The presiding judge reviewed the evidence and found no basis to overturn the jury’s verdict.”

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.

Right now, 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 partly because there's no proof yet that the drugs actually prevent heart attacks, strokes and the like—though they are immensely effective at lowering "bad" LDL cholesterol. Outcomes data are on their way, with Amgen due to report first.