Daniel Gerson, a veteran Disney and Pixar writer, has died after a battle with brain cancer. He was only 49 years old.

Gerson’s family announced his death in a New York Times obituary. He died at his home in Los Angeles.

Gerson was born in New York and graduated from NYU film school. He started writing in Hollywood at the NBC sitcom Something So Right before he went to the movies with Pixar’s Monsters Inc. in 2001. He co-wrote Monsters Inc. with Andrew Stanton.

According to The Hollywood Reporter, he also worked on 2013’s Monsters University with his longtime writing partner Robert L. Baird. The two also worked on the upcoming Cars 3 and wrote Disney’s Big Hero 6 with Jordan Roberts.

Gerson also made story contributions to several other Disney and Pixar projects, including Chicken Little, Inside Out, Up, Meet The Robinsons and Cars. He also contributed to Sony’s Open Seasons.

During his career, Gerson won a BAFTA Award and earned three Annie Award nominations. He is survived by his wife of 20 years, Beau Stacom, their two children, his parents and his sister.