Can Amgen sue its way to the top of the PCSK9 pile?

In the race to commercialize a new class of potential cardiovascular blockbusters, Amgen ($AMGN) and its team of lawyers have filed a patent suit to fend off the advance of rivals Sanofi ($SNY) and Regeneron ($REGN). But, looking at the patents in question and the history of such challenges, one analyst figures Amgen is unlikely to succeed in keeping its competitors off the market.

The companies are developing antibodies designed to block the protein PCSK9, thereby helping the body clear LDL cholesterol from the blood. Examining each party's intellectual property, ISI's Mark Schoenebaum noted a major a difference: Regeneron's patents cover alirocumab, its PCSK9 contender, while Amgen's extend beyond its own evolocumab and claim any antibody to the protein.

That's a sweeping assertion, and one that might not stand up before a judge, Schoenebaum wrote in a note to investors.

"Of course, this may be perfectly acceptable in the eyes of the court, and if that is true, then Amgen's patents appear fairly robust," he wrote. "However, common sense tells us that such broad patents may just as likely be susceptible to criticism because of the magnitude of how broad they actually are (or appear to us, at least)."

Amgen, long the leader in a PCSK9 race that also includes Pfizer ($PFE), is expecting to win FDA approval for its treatment no later than Aug. 27. That would have given it months of market exclusivity, but, over the summer, Sanofi and Regeneron paid $67.5 million for an FDA voucher that will cut alirocumab's review time down from 10 months to 6 months. Assuming the pair files its drug by year's end as planned, alirocumab will likely be up for approval at the same time if not before Amgen's contender.

In its lawsuit, Amgen demands an injunction on the manufacture, use and sale of alirocumab, an outcome Schoenebaum thinks is not very likely. Instead, the best-case scenario for the Big Biotech would be a judge ordering Sanofi and Regeneron to hand over an ongoing royalty on alirocumab's sales, according to Schoenebaum. And with peak estimates hovering around $3 billion for the treatment, even a small percentage would spell significant revenue for Amgen.

Neither company has commented on the lawsuit.

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