INDIANAPOLIS, Ind. (AP): Eli Lilly CEO John Lechleiter will retire in December after leading the drugmaker through a challenging period in which it lost U.S. patent protection for several top-selling products.

The Indianapolis company says the president of its bio-medicines business, David Ricks, will replace Lechleiter in January and become board chairman next June.

Lechleiter became CEO in 2008. He joined the company in 1979 as an organic chemist. The 62-year-old executive led the drugmaker as it lost patents protecting its all-time best seller, the anti-psychotic Zyprexa, and the antidepressant Cymbalta.

Lilly, known for its portfolio of cancer and diabetes treatments, responded to patent losses by developing new drugs, cutting expenses and drawing more revenue from the insulin Humalog and from its animal health business.