Singapore: Gilead Sciences' head of commercial operations for the past decade, Mr Kevin Young, who oversaw tremendous sales growth at the US biotechnology company, will retire next month.

Mr Young, who plans to step down on February 4, 2014, has held the top commercial post for the world's leading maker of HIV/AIDS medicines since 2004. During his tenure Gilead's annual sales grew from $1.24 billion in 2004-to-about $11 billion in 2013. Before joining Gilead, Mr Young held posts with US biotech Amgen and British drug maker AstraZeneca.

Mr Young, 56, leaves the top commercial post just as Gilead is launching what is widely expected to be its biggest and most important new therapy in years, an all-oral regimen for treating hepatitis C that has garnered analyst forecasts for eventual annual sales of $3 billion-to-$16 billion.

During his tenure, Mr Young oversaw the launch of eight new therapies, including Atripla, the first single tablet regimen for the treatment of HIV, which is the top seller for treating the virus that causes AIDS in the US and Europe, Gilead said.

Mr John Martin, chief executive, Gilead, said that, "Over the past nine years, he has greatly expanded and strengthened our commercial organization, preparing the company to introduce products in new therapeutic areas."