AbbVie Inc. has settled its Delaware patent infringement suit against Boehringer Ingelheim, granting the German drugmaker a nonexclusive license to begin selling a biosimilar of its $20 billion immunosuppressant Humira in 2023.

The companies announced the settlement with a pair of press releases Tuesday. Under the agreement, Boehringer will to pay AbbVie royalties for licensing its Humira patents and agreed to acknowledge the validity and enforceability of the patents, AbbVie said.

The companies said the settlement applied only to the United States, though the specific terms of the agreement remained confidential.

“This is an important settlement as it resolves all Humira-related patent litigation in the U.S and provides access for another biosimilar manufacturer seeking to enter the U.S.,” Laura Schumacher, AbbVie's vice chairwoman of external affairs and chief legal officer, said in a statement.

“As an innovation-driven biopharmaceutical company, we will continue to develop novel cures for the toughest health challenges and rely on a robust patent system to protect that investment in innovation,” she said.

Boehringer said the license period for its biosimilar, Cyltezo, would begin July 1, 2023, making the company one of the first to market an alternative treatment option to Humira in the U.S.

“We are proud of the role we play in raising public awareness of biosimilars and being able to stimulate competition to bring more affordable treatment options to U.S. patients,” said Sheila Denton, senior vice president and U.S. general counsel at Boehringer. ”This resolution provides clarity regarding the availability of Cyltezo and allows us to focus on serving patients who need to manage their chronic disease.”

The settlement brought to a close AbbVie's 2017 suit under the Biologics Price Competition and Innovation Act, a federal law that provides for expedited regulatory approval of drugs that are exceptionally similar to innovative products already being sold in the U.S. The Chicago-based  drugmaker claimed just eight patents in its complaint, but said it could assert dozens more if Boehringer, which had received regulatory approval, attempted to launch its copycat.

Boehringer responded with its own “unclean hands” defense, claiming that AbbVie had engaged in a “global effort” of pursuing overlapping and noninventive patents in order to create a “patent thicket” that would delay competition for its blockbuster drug. In February, U.S. Magistrate Judge Richard A. Lloret ordered AbbVie after a delay to quickly produce documents related to Boehringer's defense.

On Tuesday, AbbVie entered a stipulation of dismissal with the court, saying that all claims and defenses had been dismissed without prejudice and that each side would bear its own costs.

According to filings with the U.S. Securities and Exchange Commission, Humira accounted for 65% of AbbVie's total net revenues in 2017 and generated more than $18 billion in global sales, up 14.6% from 2016.

AbbVie was represented by William F. Lee, William G. McElwain and Amy K. Wigmore of Wilmer Cutler Pickering Hale and Dorr and Michael P. Kelly and Daniel M. Silver of McCarter & English.

Boehringer was represented by Bruce M. Wexler, Eric W. Dittmann, Isaac S. Ashkenazi, Chad Peterman, Young Park, Ashley Mays-Williams, Nicholas Tymoczko and Carl Minniti of Paul Hastings and James D. Taylor Jr., Selena E. Molina, Christopher R. Hall and Andrea P. Brockway of Saul Ewing Arnstein & Lehr.

The case was captioned AbbVie v. Boehringer Ingelheim Pharmaceuticals.