Question: Books + Movies= My new OTP

We talked previously about how an author can sell their copyrights to the movie industry in order to create a film, so I'm assuming there can be instances where it happens vice versa. Currently, I'm thinking of how the Star Wars saga and their book franchises and how that happened. 

Anyways, can an agent who failed to pitch a manuscript to any publishing industries pitch it to the movie industry? Does that count? Just generally curious between a relation (if any) between the relationship between film and literature.