No game sales numbers were released, so it's difficult to say whether Wii U has turned a profit for Nintendo yet. The best indication of sales so far are active users on Miiverse, the Wii U's integrated social network.
Currently, the two most popular games in Miiverse are Nintendo Land and New Super Mario Bros. U, with more than 50,000 and 45,000 active users, respectively.
Miiverse only keeps track of users who post in the social network's forums, so actual sales numbers are likely higher.
Wii U's 400,000 units sold is a respectable number for a new system's launch week. In fact, the Xbox 360 sold 326,000 units during the entire month of November when it launched in 2005. However, the Wii U launch falls short of the Wii's 2006 launch that sold 600,000 systems within eight days.