The new competitions will contain English and French clubs, Premiership Rugby added, but "will also be open to teams from other countries."
ERC said in its own statement that there was a "shared sense of frustration" at the continuing impasse between the competing bodies, but hopes an ERC board meeting scheduled for Wednesday in Dublin "will provide an opportunity for the parties to review the consultation process to date."
The equivalent of football's Champions League, the Heineken Cup has been running since the 1995/96 season and has expanded into a popular 24-team competition featuring the top teams from the Six Nations countries.
Its current deal runs through to the end of this season and clubs from England and France indicated in June last year that they intended to end their involvement in the competition unless a new agreement that suited them was reached.
They are unhappy that while English and French clubs have to qualify for the Heineken Cup through placings in their domestic leagues, the top teams from Italy and Scotland automatically qualify, as do three of four teams from Wales and Ireland who compete in the Pro12 league.
The ERC and the clubs of the Pro12 have given little indication of conceding ground.