Not so- Julie Newmar appears at the end, to crown John Leguizamo as Drag Queen of the Year.
A better example: Antonio is the title character of The Merchant of Venice, but he’s probably the least memorable person in the play.
Do these count?
I guess it’s up to the OP, but there musty be millions of these stories that have titles that might conceivably be construed as a person’s name but actually have no corresponding character even mentioned in the story.
Of the “Glengarry Glen Ross” and “Howard’s End” type where a peice of geography has a name that is or might be a person’s name we have “Wall Street”, “Breakfast at Tiffany’s”, “Coming to America” “Dante’s Peak”, and so on. After all there might just as well be or have been someone named “Wall” or “Dante” or “Amerigo” or"Tiffany" as someone named “Howard”. But does that really make the titles references to non-existent characters? I wouldn’t call any of those ‘people’ or Glengarry Glen Ross characters in those stories.
For every “Priscilla” we have a dozen such a “Das Boot”, “Titanic”, “Appollo 13”, “Phantom Tollbooth” etc where the title is also a vehicle’s name with absolutely no correspondence to an actual character in the story. In fact we could fill a thread with stories where the title is a vehicle’s name, particularly women’s names for ships. But once again I’m not sure that makes them minor characters rather than named props.
Wall Street is named for a wall, not a person. 
And yet you didn’t mention The Big Lebowski, where thee BIG Lebowski isn’t the main character…The Dude is.
Yes, that’s why I said “might be”. And Glenn Ross may well have been named for a physical object and not a person as well, either Rose Glen or Horse Glen. It isn’t made clear in the play that it isn’t. That’s my point. It’s a piece of geography that sounds plausibly like it might be named after a person and nothing more. There is no actual reason for even believing that it is.
I wouldn’t have thought that constitutes a character. And if it does this list is endless. Every single movie with what sounds like it might be a person’s name gets thrown in. That means every movie with the words “Rose”, “Dawn”, “America” and so on in their titles.
How about The Legend of Zelda?
Akira (the movie)
The Prisoner Of Azkaban
The Half Blood Prince
The Return Of Martin Guerre.
Sommersby
Harvey.
Jesus Christ Superstar is more about Judas, though Jesus does get some good songs.
Amadeus is really about Antonio Salieri, and his reaction to God’s favoring Mozart. Why not call it Salieri? (Or even Mozart?). Well, look at what Amadeud means.
Even though it’s really the secret of the plot, The Man Who Shot Liberty Valance was all about the James Stewart character, but John Wayne’s character turns out to be the guy referred to in the title. Too tricky to count in the spirit of the OP, but that hasn’t slowed down others so I thought I’d be cute, too.
Dr. Strangelove, or How I Learned to Stop Worrying and Love the Bomb would certainly qualify. The good doctor’s nowhere near the central figure of the whole piece…
The Trouble With Harry
Oscar (the movie with Sylvester Stallone)
The original novel The Phantom of the Opera was really about Raoul and his relationship with Christine.
Star Trek III: The Search for Spock
Lorenzo’s Oil
Mr Skeffington
The Manchurian Candidate
The Hound of the Baskervilles is really about some doctor named Watson. There’s a detective named Holmes in it for a little while, too, but the Hound doesn’t even show up until the end.
Y’know, for that matter, you never even really see Sauron in The Lord of the Rings. He’s always offstage. In the movie you get to look at his Big Glowing Eye every now and then, but you don’t get that in the book.
Willy Wonka and the Chocolate Factory - half points because it’s a rename from Charlie and the Chocolate Factory, and Charlie is the central character
Monty Python and the Holy Grail - Monty Python isn’t even in the movie! 
I don’t think these count – the full titles are “Harry Potter and [secondary character]”.
Ooops – Blake already did LoTR.
Sorry.
Hijacking for a moment, what good JC song except for GESTHEMANE (and part of EVERYTHING’S ALRIGHT)? Every other song by JC (What’s the Buzz, Poor Jerusalem, The Last Supper) is pretty whiny.