Horizon Pharma has withdrawn its roughly $1 billion unsolicited bid to acquire specialty pharmaceutical company Depomed after a California judge ruled that Horizon improperly used confidential information.

Horizon had been seeking injunctive relief regarding the legality of Depomed's poison pill from Judge Peter Kirwan of the Superior Court of California. Depomed, meanwhile, had filed a motion for preliminary injunction, accusing Horizon of improperly using information about the pain therapy Nucynta (tapentadol) that it obtained through a confidentiality agreement entered into as part of a competitive bidding process for the drug. Both Horizon and Depomed were involved in the bidding process, wooing Janssen Pharmaceuticals, a unit of Johnson & Johnson.

Ultimately, Depomed emerged as the winner for Nucynta; however, it accused Horizon of turning around and using nonpublic information about the drug to try and take over its rival. For its part, Horizon maintained the confidentiality agreement applied only to a co-promotion agreement involving Nucynta and Horizon’s Duexis (ibuprofen/famotidine) that was abandoned by the J&J unit in March 2014. The confidentiality agreement did not extend to the Nucynta auction, Horizon said, a position with which Depomed — and the court — disagreed.

Despite the setback, Horizon says the ruling does not affect its 2016 guidance or long-range plans.

The ruling came a week after Express Scripts filed suit against Horizon seeking to recover roughly $140 million, contending it refused to honor contractual obligations under a manufacturer rebate agreement.

Court documents detailing Kirwan’s decision are available here: www.fdanews.com/11-23-15-depomed.pdf.