nope "Microsoft put a lot of beef behind [Alan Wake] for it to be an exclusive for the 360," said franchise development head Oskari Hakkinen in an interview with Eurogamer. "They feel it's an important title for their portfolio. It fits into their portfolio among other games like Gears of War, Halo and Forza."
Though the game debuted 8th on the NPD charts in the US following its release--up against Red Dead Redemption--Remedy announced in July that the studio was "very pleased" with the game's performance at retail. The studio felt that the franchise "has legs".
Though Hakkinen mentions that a sequel would be Microsoft-exclusive leaving the door open for a PC version, he stresses that it could go either way with a sequel and it doesn't mean a PC version of Alan Wake 2 would be guaranteed.
Remedy is currently working on more DLC for Alan Wake and "haven't had a chance to get out to Redmond, Microsoft Game Studios, and discuss anything further of how we move on," with regards to a full sequel.