The decision was made after the pilot was shot and then HBO and Ellin attempted to rewrite the show, reports Deadline.
In the pilot, 40 starred Ed Burns, Michael Rapaport, Michael Imperioli and Adrian Pasdar as four long-time friends who help each other deal with life at the age of 40.
This isn't the first time Ellin has developed a HBO series revolving around of group of close male acquaintances. He is the creator of the comedy-drama series Entourage about a movie star and his childhood friends.
Ellin is still in contract with HBO to develop more series. Last year, HBO picked up his project Da Brick, which is said to be loosely based on the life of boxer Mike Tyson.
Watch the trailer of the final season of Entourage below: