HBO has greenlit its first Game Of Thrones prequel spinoff pilot. Emphasis on prequel though as the series, if picked up, will be set 10,000 years before the main series. So it'll pretty much be Game Of Thrones-related in name only. If picked up, the series will be showrun by Jane Goldman, who has worked on Stardust, Kick-Ass, Kingsman: The Secret Service, and the upcoming The Little Mermaid. No director, cast, or title have been announced.
At one point there were five spinoffs in the works, but according to Martin, they're down to a possible four as one has been shelved.
One of those has been shelved, I am given to understand, and of course Jane's pilot is now moving to film. But that does not mean the others are dead. Three more GAME OF THRONES prequels, set in different periods and featuring different characters and storylines, remain in active development. Everything I am told indicates that we could film at least one more pilot, and maybe more than one, in the years to come. We do have an entire world and tens of thousands of years of history to play with, after all. But this is television, so nothing is certain.
It's only a matter of time until HBO is the GOT network.