Former Guidant Corp. CEO James M. Cornelius has announced his retirement as chief executive of drugmaker Bristol-Myers Squibb Co., the company announced Tuesday.

The Trenton, N.J.-based company's board chose Lamberto Andreotti, 59, to replace Cornelius as CEO effective May 4. Cornelius, 66, will remain as Bristol's chairman. Andreotti has been Bristol's president and chief operating officer since March 2009.

Cornelius became Bristol's chairman in February 2008 after being elected CEO by the board of directors in April 2007. That was after he had served as interim CEO for about eight months.

"I said before I was a reluctant CEO," this time, Cornelius said Tuesday during a conference call. "I truly didn't have any aspirations to become a CEO" again and had to "convince my wife to move from Indianapolis to New York."

Yet, just five weeks ago, during a conference call announcing fourth quarter results, Cornelius told analysts asking about succession planning that he didn't intend to retire soon because he was still enjoying the job. He said he and his family are still discussing what's next, but that they will be moving back to Indianapolis.

Cornelius previously served as chief financial officer at Indianapolis-based Eli Lilly and Co., where he worked for nearly three decades before first "retiring" in 1995. He then retired twice from medical device maker Guidant Corp., in 2000 and again in 2006.

Cornelius served as chairman emeritus of the Guidant board of directors when it closed its merger into Boston Scientific in April 2006. Previously, he had been chairman and CEO during the merger process and was responsible for the company's initial public offering and subsequent split-off from Eli Lilly in 1995.

Prior to his role at Guidant, Cornelius was Lilly's CFO from 1983 to 1995. From 1980 to 1982, he was CEO of former Lilly subsidiary IVAC Corp.

During his time at the helm of Bristol-Myers, Cornelius initiated a strategy dubbed the "String of Pearls" to sell off noncore businesses such as its Mead Johnson nutrition franchise and buy multiple pearls , biotech companies or products in development , to transform the company into a biopharmaceutical powerhouse.

Andreotti said the company already has completed nine such deals.

The most prominent was last summer's $2.1 billion purchase of biotech company Medarex Inc. It owns successful antibody technology used to create biologic drugs that make the immune system attack cancer cells , and it has several of its own drugs in development.

Most of Bristol's competitors instead have been focused on diversifying their product lines and slashing costs.

Bristol-Myers is the maker of blood thinner Plavix, the world's second-best-selling drug.