Complex sentence: However, Leonard Nimoy dropped out of the film because he was concerned over potential merchandising after his likeness as Spock was used in a Heineken advertisement without either his permission or an arrangement for royalties.
Split into simpler sentences: However, Leonard Nimoy dropped out of the film. He was concerned over potential merchandising following his likeness as Spock being used in a Heineken advertisement without either his permission or an arrangement for royalties.