This is probably a good thing. For a time, Sylvester Stallone was considering making a Rambo movie in which Rambo would have fought an immortal, werewolf-like monster that was both a genetically-engineered bipedal biological weapon, carrying the DNA of an entire race of murderous savages within it, and simultaneously the reincarnation, or perhaps it would be more appropriate to say “re-embody-ing”, of an archfiend from Hell itself. (Huggins is a combination Christian/Horror/Action Adventure writer, and his works typically feature spiritual themes overlapping with cutting-edge technology.) But Stallone wisely decided to go a different route with the next Rambo flick.
Reportedly Sly still intends to make and star in a movie based on HUNTER, the novel by James Byron Huggins upon which he would have based that unmade Rambo film. But considering that Stallone has been sitting on the rights to the novel for well over twenty years—I used to know Byron Huggins personally, and I remember him telling me about it when Stallone bought the film option for the book—I wouldn’t hold my breath on this one. Why Sly never got around to making a HUNTER movie I don’t know. Nor do I know if he ever will.