HBO, the pay-cable network, is negotiating with...

HBO, the pay-cable network, is negotiating with promoters Don King and Butch Lewis for a series of fights that could lead to the first undisputed heavyweight champion since Leon Spinks held that honor in 1978.

Currently there are three heavyweight champions: Tony Tubbs, recognized by the World Boxing Assn.; Pinklon Thomas, recognized by the World Boxing Council, and Michael Spinks, the former light-heavyweight champion who upset Larry Holmes for the International Boxing Federation title.

Bob Greenway, HBO vice president for sports programming, said that negotiations with King and Lewis were being held for a series of seven title fights that could lead to one champion in 1987.