In an interview with Forbes, BioWare co-founders Ray Muzyka and Greg Zeschuk were asked about the future of Mass Effect once the current trilogy is brought to a close. Here is the answer that they gave:
Greg Zeschuk: Certainly the setting has really resonated with people, the type of aliens in the world, the type of people that inhabit space. Obviously we focus first and foremost on nailing it on this game, and then, you know, the possibilities in the future are very, very broad.
Ray Muzyka: We want to make sure its awesome. [Mass Effect 3] is our first focus. Beyond that, we do have a desire to continue the Mass Effect franchise, and were working on the details, figuring out what the fans want, figuring out the right way.
Click below for the full interview.