One of AbbVie Inc.’s patents on its top-selling arthritis drug Humira may be invalid, a US agency said Tuesday, agreeing to consider a challenge filed by Coherus Biosciences Inc.

Coherus has shown a “reasonable likelihood” that it will win the challenge, the Patent Trial and Appeal Board said in a decision instituting a formal review of the patent. AbbVie shares dropped 3.5 percent, while Coherus rose 16 percent on the news.

The patent, issued in 2014 on an application first filed in 2002, covers the bi-weekly dosing of Humira to treat rheumatoid arthritis. The agency is still considering petitions Coherus has filed on three other Humira patents.


The patent “constitutes one of the cornerstones of the Humira IP estate, so the decision represents an important toehold for biosimilar developers to get around AbbVie’s patent defenses,” Geoff Meacham, an analyst with Barclays Plc, said in a note to clients.

Getting the board to agree to review the patent was just the first hurdle. A trial will be held, and a final decision will come in about a year. Either side could then take the case to an appeals court that specializes in patent law.

Meacham said the agency’s decision to consider Coherus’s petition increases the chances it also may institute a review on petitions filed by Boehringer Ingelheim GmbH on the same patent. He said a competitor to Humira could come in 2019 or 2020.

Coherus contended the patent is invalid because the dosage regimen it covers was a “routine optimization of the therapy” that was known by researchers. It’s made similar arguments seeking to cancel two other Humira patents. The third patent, subject of a petition filed May 9, covers a formula to make the drug.

AbbVie had urged the board not to review the patents, saying Coherus “merely rehashes the same arguments thoroughly considered by the examiner” during the application process and uses hindsight to ignore “critical efficacy and safety issues.”


The patent office, in agreeing to review the patent’s validity, said AbbVie’s arguments are “best resolved during trial.”

“At this stage of the proceeding, and based on the current record, we are persuaded that there is a reasonable likelihood” that Coherus would prevail in its argument, the three-member panel of administrative patent judges wrote.

Humira, given by injection, is
AbbVie’s biggest drug, generating $14 billion in 2015 sales, about 61 percent of the company’s revenue.

Loss of patent protection or the entrant of a biosimilar version of the drug could have a “material adverse impact” on AbbVie’s operations, the company said in its annual report.

The review process at the agency has been criticized by the pharmaceutical industry because it has a high rate of decisions invalidating patents.

Coherus soared $2.58 to $18.85 at 4 p.m. in New York trading of 1.6 million shares, almost seven times the three-month daily average. AbbVie fell the most since February, closing at $60.25.