A novel that tells a loosely disguised true story, using fictional names for the characters, can be called a roman a clef.
Both The Bell Jar by Sylvia Plath and The Sun Also Rises by Ernest Hemingway are believed by many to be romans a clef, stories based on events in the authors' actual lives. The characters in both books have made-up names, but like many romans a clef, they are recognizable as real people. In French, roman à clef means "novel with a key," with the "key" being the hints the writer gives about the relationship between fact and fiction.