DLA Piper LLP can’t represent a pharmaceutical company suing former DLA client Horizon Healthcare Services Inc. over coverage of hemophilia drugs, a federal judge ruled.

The firm represented an affiliate of BioMatrix Specialty Pharmacy LLC on matters “directly adverse” to Horizon while it still counted Horizon as a client, Magistrate Judge Barry S. Seltzer of the U.S. District Court for the Southern District of Florida said.

This conduct violated the Florida Bar’s ethical rule on conflicts of interest, Seltzer said in a Dec. 27 disqualification order.

The dispute began when a DLA Piper attorney representing BioMatrix affiliate BiologicTx on other matters asked the firm’s “relationship partner” with Horizon to speak to the insurer about a billing dispute. DLA characterized these communications as a “professional courtesy” that didn’t rise to the level of legal representation. Seltzer disagreed.

“DLA Piper effectively leveraged its relationship with Horizon for the benefit of BiologicTx,” Seltzer said.

Attorney disqualification, while not mandatory, was warranted in this case because DLA Piper’s actions resulted in Horizon “unwittingly disclosing its confidences about an adverse party to that adverse party’s law firm,” Seltzer said.

The underlying lawsuit accuses Horizon, which insures more than 3 million people in New Jersey, of wrongfully denying coverage for high-cost specialty drugs in violation of health plan terms.

GrayRobinson PA represents Horizon.

The case is Biomatrix Specialty Pharmacy, LLC v. Horizon Healthcare Servs., Inc., 2018 BL 479962, S.D. Fla., No. 0:18-cv-61680-FAM, 12/27/18.