Ketchum and The Zeno Group are understood to be among the agencies pitching for the account.
GSK declined to disclose details about the review process and how many drugs would fall under the remit of the account. Incumbent agency Public Communications Inc (PCI) said it would not repitch.
The drugs giant markets seven HIV treatments, including Combivir and Trizivir, and is market leader in the category, with competition from Bristol-Myers Squibb and Abbott Laboratories. The company's US sales of HIV therapies rose eight per cent in the first quarter of this year.
GSK's pipeline includes four compounds that are undergoing clinical trials. In addition, the company is awaiting US approval for a combination tablet, already approved in Europe.
PCI worked with GSK on its Magic Johnson-backed campaign for the promotion of an HIV drug in 2002.
HIV is also a significant component of GSK's corporate social responsibility efforts, which include donating drugs to developing countries.
Although all companies that make HIV drugs have faced backlash from activists over the pricing of products in developing countries, GSK has been under particularly heavy fire.