Apparently the duo left the project after director David Fincher became involved with the film.
"Once they got David Fincher on," Gaiman said, "David explained his process consisted of having over ten drafts, done over and over, and Roger and I were sort of asked if we wanted to, if we were interested in doing that. And we definitely weren't."
Fincher still has Gaiman and Avary's latest draft, but it is uncertain where Fincher will proceed from there.
"So we'll wait and see what happens," he said. "I just hope whatever happens, it's faithful to Black Hole."