 John Cazale (qv) was very weak when filming began, and for this  reason, his scenes were filmed first. Michael Cimino (qv) knew  from the start that Cazale was dying from cancer, but the studio did  not. When they found out, they wanted to replace Cazale. When  Meryl Streep (qv) learned of their intentions, she threatened to  quit if they did. Cazale died shortly after filming was completed.