The Immortal (1970)

"This man has a singular advantage over other men. Ben Richards is immune to every known disease including old age. Periodic transfusions of his blood can give other men a second, a third lifetime, perhaps more... Ben Richards will live longer than anyone has ever lived, but a transfusion to the wrong man could make him a prisoner for all time. And so he runs from the hunters, the human hounds who would cage him."