According to this Sci Fi Wire article, Tom Cruise mentioned he’s no longer involved with the Iron Man movie project.

“I need to be able to make decisions and make the film as great as it can be, and it just didn’t go down that road that way,” he said. He added: “I’ve never just made a movie to make a movie. I’ve always made them because I really was interested in the story. I wanted to make that kind of picture and see what it would take, and it was an adventure for me. For that, it just wasn’t panning out. So far. You know, as of yet.”