In a lengthy post on the official BioWare blog, the Studio Director of BioWare Montreal has revealed that his studio will be working on a new game in the Mass Effect series. BioWare Montreal has already been heavily involved with the previous Mass Effect games, including the development of many missions, cinematics, and DLC for both Mass Effect 2 and Mass Effect 3, as well as the lstter's multiplayer mode. As such, it has been positioned as the natural successor to the series.
The next Mass Effect game is still very early in development, and it appears that its developers are still working on new gameplay and story ideas. Much like the upcoming Dragon Age III, the game is being built with the Frostbite 2 engine. Because of this, it will take advantage of many of the resources for that engine that have been developed by the Dragon Age team. Other than that, little is known, so fans of the series who are curious about how it will continue after the conclusion of the original trilogy will need to be patient.