U.S. drugmaker Bristol-Myers Squibb said on Sunday it has named Francis Cuss to become its next chief scientific officer after Elliott Sigal retires as head of research and development on June 30.

Sigal, 61, who has led Bristol's research efforts since 2004 and has overseen the approval of 14 new medicines on his watch, will also resign from the company's board of directors, the company said. Bristol had not previously announced Sigal's retirement plans.

Cuss, 58, is set to take over the top scientific post on July 1. He joined Bristol-Myers in 2003 after spending 14 years working at Schering-Plough and three with British drugmaker GlaxoSmithKline.

"As our company embarks on the next phase of pipeline execution, this is a natural time for Francis to lead our R&D team," Chief Executive Lamberto Andreotti said in a statement, adding that Cuss has been a key member of the R&D team with experience in both drug discovery and development.

The Bristol-Myers news comes a month after Merck & Co announced that its research chief, Peter Kim, would retire and be replaced by Roger Perlmutter, who had previously been head of research and development for biotechnology company Amgen. That transition is set to take place next week.

Cuss has been instrumental in advancing development of some of the company's highest profile experimental medicines, the company said, including drugs being tested against hepatitis C and cancer, such as a promising cancer immunotherapy from a new class called PD-1 inhibitors.

Sigal joined Bristol-Myers in 1997 as vice president of the department of applied genomics and has held several posts since. He was elected to the board of directors in 2011.

Under Sigal's leadership, new Bristol-Myers products have been introduced for a wide variety of illnesses, including medicines to treat cancer, mental illness, HIV/AIDS, hepatitis B, rheumatoid arthritis, diabetes, organ transplant rejection and heart disease.

Andreotti thanked Sigal for his service, saying he had "a significant impact on the transformation of our company."

Bristol-Myers shares are up nearly 25% this year and more than 60% since Andreotti took over as CEO in 2010.