No, the XCOM shooter is not being scrapped and built from the ground-up.  Another XCOM game is coming as well.

Announced in the February cover reveal of Game Informer, XCOM: Enemy Unknown will return to its roots as a full-on strategy game developed by Firaxis Games.  Players will control the XCOM commander and defend the Earth from an alien invasion.  Players will have to manage resources, technologies and oversee combat strategies and individual units as it battles back the alien menace.

"We're looking forward to building upon the core gameplay experiences that fans of the original X-COM love, while introducing the franchise to a new generation," said Sarah Anderson, senior vice president of marketing for 2K in a press release. "With Firaxis' XCOM: Enemy Unknown and 2K Marin's upcoming XCOM, 2K Games will be offering two different gameplay experiences drawing from the classic X-COM universe. Each game offers a unique XCOM experience in different genres, as envisioned by two different studios with unique creative visions."

The game is scheduled for a fall 2012 release and will be available for the PC, Xbox 360 and PS3.