Here's a breakdown:
* Fullmetal Alchemist (2003 anime): This anime adaptation deviates significantly from the manga after a certain point. It creates its own original story, exploring different themes and characters. It's a complete story in itself, but doesn't follow the manga's ending.
* Fullmetal Alchemist: Brotherhood (2009 anime): This anime adaptation is a faithful adaptation of the manga. It follows the original story and characters closely, including the original ending. It's considered the definitive adaptation of the Fullmetal Alchemist manga.
So, while both anime adaptations are based on the same manga, they are ultimately different stories with separate plots, characters, and endings.