PTO shuts down Amgen's Humira IP challenge

Amgen ($AMGN) has hit a potential snag in its quest to bring a biosimilar of AbbVie ($ABBV) cash cow Humira to market.

Thursday, the U.S. Patent and Trademark Office declined to review a pair of formulation patents on the arthritis drug, determining that "based on the petition and the accompanying evidence … Amgen has not shown a reasonable likelihood of prevailing on any of its challenges," Reuters reports.

It's a win for AbbVie, which said earlier this week that it expects Humira--currently the best-selling drug in the world--to reach $18 billion in sales by 2020, the news service notes. The Illinois pharma, which has repeatedly expressed confidence in its IP protection surrounding the therapy, doesn't expect biosimilar competition to start eating away at sales until 2022.

Amgen, though has other ideas--and other avenues open to it if it wants to keep challenging AbbVie's patents. While the PTO shut down its attempt to upturn AbbVie's patents using the so-called inter partes review system--a patent-challenging shortcut recently popularized by hedge fund manager and short seller Kyle Bass--it can still go up against the drugmaker in court. And that's something it said it intends to do.

"Although we are disappointed by the PTO's decision, we continue to question the validity of the patents," the California drugmaker said in a statement seen by Reuters.

Right now, Amgen is leading the race to bring a knockoff of AbbVie's near-$14 billion seller to market, in November announcing it had become the first to file with the FDA for approval. But plenty of others are in the mix, too, including a Baxalta/Momenta team that revealed in October that they were on their way to Phase III trials.

And Amgen, whose products have come under attack by biosimilar competitors of their own, could certainly use a slice of Humira's chart-topping haul. Right now, the Big Biotech's Neupogen is the only med facing biosimilar competition in the U.S., thanks to copycat Zarxio from Novartis' ($NVS) Sandoz. And in October, the Swiss pharma giant announced that the FDA had accepted its regulatory submission for a potential biosimilar of Amgen's anti-TNF behemoth Enbrel.

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