STAYING STATESIDE: AbbVie is one company that retreated from plans to buy overseas competitors and shift corporate headquarters offshore. Kristoffer Tripplaar / Sipa USA

AbbVie Inc. filed a patent infringement lawsuit Wednesday against German rival Boehringer Ingelheim Pharmaceuticals Inc., the second case in Delaware that seeks to block sales of a less-expensive biosimilar version of Humira, AbbVie’s top-selling drug.

The suit accuses Boehringer of infringing dozens of AbbVie’s patents in a bid to bring its copy of the anti-inflammatory treatment to market under a federal law that provides for expedited regulatory approval of drugs that are exceptionally similar to innovative products already being sold in the United States.

Though the Chicago-based drugmaker’s 70-page complaint focuses on just eight patents, the company threatened to pursue further litigation on up to 66 patents if Boehringer’s copy is approved. Approval from the U.S. Food and Drug Administration—and additional litigation—could mean that it will be years before Boehringer’s product launches.

“Although the BPCIA allows Boehringer an abbreviated regulatory pathway, it does not give Boehringer a license to infringe AbbVie’s intellectual property,” AbbVie said in its 70-page complaint, filed in the U.S. District Court for the District of Delaware.

A spokeswoman for Boehringer did not immediately provide comment Wednesday on the lawsuit.

AbbVie has been aggressively moving to protect its blockbuster drug, which accounted for 63 percent of the company’s total net revenues in 2016. With a list price of more than $50,000, Humira generated $10.4 billion in sales in 2016, filings with the U.S. Securities and Exchange Commission showed.

Last August, AbbVie brought a similar case in Delaware federal court against Thousand Oaks, California-based Amgen Inc., also alleging infringement and violations of the Biologics Price Competition and Innovation Act. In October, AbbVie agreed to drop the BPCIA claim after Amgen said it would honor a provision of the law that requires a 180-day notice of commercial marketing once the FDA approves a biosimilar application.

But that case is not expected to go to trial until 2019, and Amgen told Bloomberg BNA last year that it had delayed the launch of its biosimilar through at least 2017.

On Wednesday, AbbVie accused Boehringer of using its patents to capitalize on the clinical success of Humira, which has been approved to treat 10 different diseases, including different types of arthritis and Crohn’s disease.

An AbbVie spokeswoman did not immediately comment on the suit or the company’s efforts to protect its blockbuster drug. But AbbVie did warn investors in an annual SEC filing that Humira was subject to competition from more affordable biosimilars, a development which would cut into the drug’s revenues.

On Wednesday, the company said in its complaint that it expected more litigation was likely on the way.

“AbbVie seeks an injunction to prevent Boehringer from engaging in widespread infringement of the eight patents in this Complaint,” it said. “AbbVie also reserves its right to assert the remaining patents infringed by Boehringer in a second wave if and when Boehringer provides a notice of commercial marketing, or as circumstances otherwise warrant.”

An online docket-tracking service identified Benjamin J. Schladweiler and Nicholas D. Mozal of Ross Aronstam & Moritz as local counsel for AbbVie. The complaint also listed attorneys from Wilmer Cutler Pickering Hale and Dorr, Latham & Watkins and Finnegan, Henderson, Farabow, Garrett & Dunner as representing the company.

Attorneys for Boehringer were not yet listed.

The case is captioned AbbVie v. Boehringer Ingelheim Pharmaceuticals.