UPMC hospitals and physicians will be available to Highmark Inc. insurance customers at in-network rates through June 30, 2013, under a new agreement the warring companies announced this morning.

Citing the influence of Gov. Tom Corbett and a mediation process, the companies agreed to extend physician contracts for a year until hospital contracts expire.

In a statement, UPMC noted that the agreement also will allow time for regulators to examine Highmark's acquisition of West Penn Allegheny Health System.

"We are grateful to the Governor and his mediators for conducting an informed and constructive process with patient care and access the highest priority," UPMC said in its statement.

Highmark spokesman Michael Weinstein this morning said it is hoped that the stopgap measure will pave the way for a longer-term solution involving a new contract between the two healthcare giants.

"We're going to continue to work toward achieving a long-term contract with UPMC that guarantees that our members have access to all UPMC hospitals and doctors, and that's preserving provider-choice in the marketplace."

Mr. Weinstein would not disclose any details about the negotiations that led to the agreement. He would not reveal who was involved from Highmark or if there was a third-party mediator other than the governor's office.

"We're not getting into the details," Mr. Weinstein said.

He lauded the Legislature for its role in hammering out a short-term solution, citing in particular the work of state Sens. Don White, R-Indiana and Jay Costa, D-Forest Hills, as wells as state Rep. Randy Vulakovich, R-Shaler.

"The actions by the Pennsylvania state Senate and the Pennsylvania House of Representatives have been instrumental in helping to achieve the result that we have today on behalf of Highmark members because the House passed legislation, a Senate committee passed legislation, and so we're applauding those efforts in helping to achieve this result," Mr. Weinstein said.

The senators sponsored a bill that would give the Pennsylvania insurance commissioner greater authority to extend terms, by up to three years, of a UPMC-Highmark contract. Their legislation cleared a Senate committee last week.