The University of Pittsburgh Medical Center has launched another volley in the ongoing dispute with Highmark and West Penn Allegheny Health System, filing a suit in federal court in Pittsburgh alleging that Highmark has started a campaign of false advertising in an effort to steer patients away from UPMC.

Earlier this summer, UPMC asked the court to enforce a settlement agreement between it and Highmark in a high-profile antitrust case that has been pending for years.

In the suit filed this week, UPMC alleges that its major competitor in the Pittsburgh market has started an advertising campaign to make the public falsely believe that UPMC will stop accepting Highmark health insurance customers next year.

Highmark plans to "aggressively defend" its ads, said Aaron Billger, spokesman for Highmark, in a written response to a request for comment.

"Competition between UPMC and Highmark has intensified with the Pennsylvania Insurance Department's April 29, 2013, approval of the affiliation between Highmark and West Penn Allegheny Health System," UPMC said in its complaint.

"In this new environment, competition for health insurance subscribers and health care patients is fierce," UPMC said.

UPMC alleged in court papers that Highmark's campaign is indicative of its continued "unlawful conduct" toward UPMC and will, therefore, entitle UPMC to collect enhanced damages as well as attorney fees.

It noted an earlier suit, from 2001, when the tables were turned.

"Highmark took the position in that lawsuit, and convinced the United States district court, that it was false to represent that out-of-network access was tantamount to no access," UPMC said in its complaint. "The court concluded that Highmark 'subscribers do indeed have access to the disputed [UPMC] facilities and world-renowned doctors,' when they use the facilities and physicians on an out-of-network basis, even if 'at a lower level of benefits.' Highmark cannot take a contrary position to justify its advertisements now."

The newly-formed affiliation between Highmark and West Penn Allegheny Health System has altered the health care market in Pittsburgh and has heightened competition for patients, UPMC argued in its complaint. It estimated that Highmark's advertising campaign could cost it 41,000 patients, causing irreparable harm.

Subscribers to Highmark's insurance plan will have out-of-network access to all of UPMC's facilities and they will have access to certain UPMC facilities on an in-network basis, according to the complaint.

"Should subscribers want full, in-network access to UPMC after 2014, Aetna, Cigna, UnitedHealthcare, Coventry, and the UPMC health plan can and will provide it," UPMC told the court in its complaint.

In response to the suit, Billger said, "Highmark Health Services launched its current campaign about choice and affordable access in health care because UPMC continues to mislead the community about its refusal to negotiate a new contract with it and the potential negative impact of its actions on hundreds of thousands of people in Western Pennsylvania. UPMC ignores the reality that its exorbitant charges for hospital services will preclude use of UPMC facilities by Highmark members unless there is a contract between the two organizations that makes care affordable."

The dispute stems in part from a 10-year contract signed in 2002 under which UPMC agreed to provide in-network care for Highmark subscribers, according to the complaint. On the eve of the contract's expiration, in 2011, Highmark's plan to acquire the West Penn Allegheny Health System became public and UPMC announced that it wouldn't renew the contracts if the acquisition happened, according to the complaint.

A deal brokered in part by Governor Tom Corbett in the spring of 2012 would extend in-network access to UPMC hospitals to Highmark subscribers through 2014 and the same access to some facilities beyond that, according to the complaint.

"Allowing Highmark to falsely assert that UPMC will 'deny access,' 'close its doors,' or otherwise not provide care to Western Pennsylvanians gives Highmark an immediate unfair competitive advantage in the provision of health care services," UPMC said in its complaint. "These false statements attempt to push individuals toward Highmark's own Allegheny Health Network and away from UPMC hospitals and physicians."

Saranac Hale Spencer can be contacted at 215-557-2449 or Follow her on Twitter @SSpencerTLI.