He died last Sunday in a Las Vegas hospital from complications related to the disease, said Mary Skrenes, a friend and writing partner on "Omega" and other comics.
The "Howard the Duck" series became a fast hit after its January 1976 debut on Marvel and remains a cult favorite. Its lead, a disgruntled duck from another universe with a bombshell sidekick named Beverly "Thunder-Thighs" Switzler, was hailed as both smart and subversive.
The adjectives could be applied to Gerber, Skrenes said.
"Howard was his voice. Steve was able to do social commentary and sort of sneak it up on you," she said. "Sometimes it was obvious what the message was thele, and other times is was really subtle because it took place in a mystical realm or outer space."
Or in Cleveland, where Howard was a lone talking duck "trapped in a world he never made!" according to the comic's tagline.
Gerber split with Marvel in 1978 amid a dispute over the rights to the character. He sued the company and settled out of court.
Skrenes said Gerber was not closely involved in George Lucas' 1986 "Howard the Duck" film, which fared poorly at the box office.
Gerber also worked in television as a story editor on "G.I. Joe" and "Dungeon & Dragons."
More recently, Gerber and Skrenes created "Hard Time" for DC Comics, the story of a 15-year-old boy convicted in a Columbine-like school shooting who discovers he has special powers. Gerber was working on a revival of the DC Comics' Dr. Fate series at the time of his death.
"He was the kind of guy people would give an old, moribund idea to and he would come up with a fresh idea for it," said Mark Evanier, a friend.
Gerber was born Sept. 20, 1947, in St. Louis and received a bachelor's degree from St. Louis University, before joining Marvel as an assistant editor in 1972. He is survived by his mother, Bernice; his daughter, Samantha Voll; and three siblings.