Gilead Sciences Inc. Chief Executive Officer John Martin, under whom the company developed one of the fastest-selling drugs of all time, will step down and be replaced by Chief Operating Officer John Milligan.
Martin, 64, will remain as executive chairman. He has served as CEO since 1996, a year when the company's total market valuation, about $1 billion, was less than the company's two blockbuster hepatitis C treatments now bring in in a single month.
Milligan, 54, joined Gilead in 1990 as a research scientist, with a Ph.D. in biochemistry, according to the company's website. He became CFO in 2002, and COO in 2007.
The company's shares fell 3.5 percent to $84.35 in early trading in New York. Over the last five years, they have gained more than five-fold, far outpacing gains in broader indexes. The company is scheduled to report fourth-quarter earnings next week.