North Chicago’s AbbVie’s science chief to retire

North Chicago-baseed AbbVie Inc.’s longtime head of research will retire from the drugmaker, leaving the newly spun off company without a leader for its efforts to develop new medicines and buttress its future prospects.

Chief Scientific Officer John Leonard, 55, will retire in the next few months, AbbVie said today in regulatory filing. The company didn’t name a successor to Leonard, who has been with AbbVie and its parent, Abbott Laboratories for about 21 years.

The drug company has been trying to diversify its products past Humira, a rheumatoid arthritis injection that sold $9.27 billion last year and made up 50 percent of sales. One top product, a kidney drug called bardoxolone methyl, failed in final-stage clinical trials last year. Another treatment for the viral infection hepatitis C is in the last stage of testing.

Leonard “will be involved in the transition process for naming his successor,” the company said in the filing. AbbVie split from Abbott at the beginning of this year in a move to let each company focus on its core product lines of drugs and medical devices, respectively.

Jennifer Smoter, a spokeswoman for AbbVie, declined to elaborate further on Leonard’s departure. “We will announce future organizational plans at a later date,” she said in an e- mail.