WASHINGTON — The Federal Communications Commission agreed March 23 to respond to a four-year-old petition asking it to repeal the primetime access rule, which prohibits top-50-market network affiliates from airing off-net fare in the hour leading into primetime.Within the next month, it will invite public comment on a petition from First Media L.P. to jettison the venerable regulation as a violation of broadcasters’ First Amendment rights. After reviewing the comments, it will “consider initiating a proceeding to assess the continuing need for the primetime access rule,” it said. The schedule was presented in a filing before the U.S. Court of Appeals for the District of Columbia, which is weighing First Media’s suit against the FCC for ignoring its request. The company contends the delay has been “egregious,” even for an agency known for its deliberateness in such matters. The FCC defended its inaction, insisting it’s been busy pondering the financial interest and syndication rule — a far more complex and controversial proceeding. It only makes sense to defer consideration of PTAR until appeals over fin-syn have been exhausted, the agency said. But it told the court that before April 22 it will seek comment on the First Media petition as well as other pending requests for repeal of the access rule and its various aspects. It said initial comments filed in response to the petition are “no longer current” in light of its fin-syn regs. It specifically invited parties to comment on whether the new fin-syn policy would affect the need or desire for PTAR. Following an evaluation of comments on the petition, an inquiry would explore the public-interest implications of the rule, First Media’s challenges and other matters.