NEW YORK - Former President Clinton's foundation has signed pricing agreements with several suppliers involved in making a malaria-fighting drug in an effort to stabilize the medication's fluctuating costs and ensure more dependable availability.

The foundation described the agreements to The Associated Press ahead of an announcement Clinton was to make Thursday at the organization's Manhattan headquarters.

The former president in 2002 established an HIV/AIDS initiative that sought to negotiate lower prices for antiretroviral treatments, and he since has expanded his focus to include malaria treatments such as artemisinin-based combination therapies, or ACTs.

Artemisinin is an extract of the plant known as wormwood or sagewort. One of the factors making the price of artemisinin so volatile -- fluctuating from $155 to $1,100 per kilogram in recent years -- has been a wildly erratic cycle of shortage and excess of the extract, the foundation said.

Clinton has negotiated with six suppliers involved in producing ACTs that have agreed to price ceilings that the foundation says will help keep prices constant and not so dependent on the fluctuating cycles.

The agreements are with two suppliers at three levels of the supply chain -- raw material, processing and final formulation -- and the foundation hopes to add more suppliers.

About 500 million people are sickened each year by malaria, and more than 1 million die from the infectious disease, which is spread by mosquito bites. Symptoms include fever, chills, nausea and shortness of breath.

"Today's announcement is an important step forward in global efforts to increase access to affordable and effective malaria treatment," Clinton said in a statement, "and I applaud the commitments of these companies to lower volatility in this market and offer low and sustainable prices that will save more lives."

Besides benefiting from a more stable market, the suppliers that join the Clinton effort also get business and marketing assistance from the foundation.