At Saturday's My Cup O'Joe Panel at the New York Comic Con, Tom Brevoort talked about FF and Fantastic Four #600.
"November is not only Fantastic Four #600, but it is the Fantastic Four and Marvel's 50th Anniversary. So we are doing an enormous 100 page monstrous issue. Jonathan Hickman has written every page of it. It's got a bevy of stories wrapped in beautiful covers, one by Joe [Quesada], and other good ones by Gabriel Dell'Otto, Arthur Adams and some other surprises. It's a big massive celebratory package.
FF will contine in its current form, along side Fantastic Four with Jonathan Hickman writing both series from this point on starting in November."