Before the production of Scream 4, Kevin Williamson had an idea of revitalizing the franchise with another trilogy. After some creative differences during the filming and a not-so-impressive box office, the scenario has changed a lot.
Some news floated the web and this is what we have, by now: The Weinstein Company has interest in doing another sequel, there was some talking in finding a new screenwriter but there's no solid development so far. Add to this the fact that Williamson is very, very busy and took the serial killer concept to a new drama, now in pre-production (by the way, Scream 4's Nico Tortorella just signed on to this, and so did actress Natalia Zea).
AssignmentX interviewed the screenwriter recently. In the middle of it, the reporter asked about Scream 5: Generations (note: this horrible sub-title was used in Japan, but it is not official). Williamson was very succinct:
I don’t know. I’m not doing it.