I'm not sure how much of the plot in this movie was actually in the novel "The Prize"(a best-seller, I understand), but with Lehman scripting, it sure had its links to North by Northwest:
Newman finds dead man in room with TV, is attacked, brings cops back, no dead man, no TV...a lady who says Newman is crazy(NXNW: return to Glen Cove mansion/library).
Newman chased on bridge by truck(crop duster scene)
Newman chased by killer spies into...nudist meeting...makes a nuisance of himself to get cop escort out(he even has Grant's line "Why do you think I sent for you?"
Finale: knife wielding henchman falls to death (onto a monumental structure.)
That said, Lehman also seemed to have lifted the Foreign Correspondent gambit of "a substitute professor" planted for the actually kidnapped professor(Eddie G, here.)
And yes, though made three years BEFORE Torn Curtain, the presence of Paul Newman in a Cold War plot set in Scandanavia anticipates Torn Curtain, where Newman isn't allowed to be as funny as he is here.
I like The Prize, but it shows you what happens when Hitchcock isn't at the helm. The action sequences aren't very good; too many bad lines are allowed in, and the overall shape of the story is much less compelling and tight than the best Hitchcocks. This IS North by Northwest lite, and it demonstrates why NXNW is so good and hard to match.
As for Paul Newman, I grew to like his performance here, but where Cary Grant was cool and deadpan in NXNW, Newman is over-the-top and mugging a bit too much here for my taste, albeit playing somewhat of a drunk.
The Prize is more "fun" than Torn Curtain (and certainly sexier with Elke Sommer leading a cast of beauties), but I think Hitchocck at half speed with Torn Curtain has a bit more "gravitas" than this.