David Cogan, who co-produced the landmark drama “A Raisin in the Sun” on Broadway in 1959, died of lung cancer Feb. 7 at his home in Bedford, N.Y. He was 78.He had been a theater manager, owner and producer, and also founded a management firm that served celebrity clients including Anne Bancroft and Neil Simon. The firm, Cogan, Bell & Co., also represented the classical Beaux Arts Trio and psychoanalyst Erik Erikson. In 1959, Cogan and music publisher Philip Rose together produced Lorraine Hansberry’s drama “A Raisin in the Sun,” the first production on Broadway by a black playwright. It was directed by Lloyd Richards and starred Sydney Poitier. Cogan produced other plays, including 1962’s “In the Counting House,” and owned the Biltmore Theater from 1960 to 1986.