Apparently, it is a prequel of sorts. About the project, Schwartz stated, "I'm very well aware that I'll be bludgeoned by purists, but I love its mythology, and it comes with a pretty hefty paycheck."
Apparently, Josh wants to utilize some lesser known mutants in this next outing. The main plot will center on a teenage prodigy stationed at the Xavier Institute for Higher Learning. About this, Schwartz said, "It's not like I'm adding new characters like Toaster Head, or anything like that. The Incredible Hulk looks like it's going to be terrible. And why does he look like he's fighting against the monster from Cloverfield? I mean, with Transformers, it's not like fans were going to come back saying, 'You used the wrong car.' This, however, is a different story. Brett Ratner didn't have a lot of credibility going in to the third X-Men movie, but I think Bryan Singer [who directed the first two installments] got a free pass on Superman Returns because of his work on X-Men."
X-Men 4 does not have a production start date at the moment.
X-Men: First Class was released June 3rd, 2011 and stars James McAvoy, Laurence Belcher, Michael Fassbender, Bill Milner, Kevin Bacon, Rose Byrne, Jennifer Lawrence, Beth Goddard. The film is directed by Matthew Vaughn.