There have been several pretty close ripoffs. Can you think of any more?
I'll also include the "official" sequel, as Escape from LA (1997) was much more of a ripoff remake than a real sequel.
We also have:
After the Fall of New York (1983) Low budget Snake Plissken, Michael Sopkiw, is forced to retrieve the last fertile woman on earth from the ruins of New York.
No Escape (1994) Ray Liotta Snake Plissken must escape from a penal colony on a jungle island.
Doomsday (2008) Woman Snake Plissken Rhona Mitra has to enter a plague-ridden Scotland to retrieve a cure that Scottish scientists may have developed.
Lockout (2012) Wisecracking Guy Pearce Snake Plissken must infiltrate a prison spaceship to rescue the President's daughter. Apparently this ripoff was so blatant it caused John Carpenter to successfully sue director, Luc Bisson.
Are there any others? I'm sure I must have overlooked some low-budget '80s or '90s productions. Note: I am not including "1990 The Bronx Warriors" as that was much more of a Warriors ripoff.