In 2006 Health Affairs published "Developing Drugs for Developing Countries" by Henry Grabowski, Jeffrey Moe, and David Ridley. They proposed a prize called a Priority Review Voucher to be awarded to the developer of a treatment for a neglected disease. In 2007 Senators Brownback (R-KS) and Brown (D-OH) sponsored an amendment to the Food and Drug Administration Amendments Act of 2007. President Bush signed the bill in September 2007. Below you can find more information about the paper and the law.

• Paper: David B. Ridley, Henry G. Grabowski, and Jeffrey L. Moe. "Developing Drugs for Developing Countries." Health Affairs. 2006. Vol. 25, No. 2: 313-24. Appendix
• Comments from Senator Brownback: “After reading their proposal in Health Affairs, I met with Ridley and colleagues to discuss the idea further, and I subsequently drafted an amendment…Indeed, their idea is the heart of my Elimination of Neglected Diseases (END) amendment.” The Senator's complete comments are available at Health Affairs.
• Comments from Bill Gates: In his speech at the World Economic Forum in Davos in 2008, Bill Gates described the PRV: “But some of the highest-leverage work that government can do is to set policy and disburse funds in ways that create market incentives for business activity that improves the lives of the poor. Under a law signed by President Bush last year, any drug company that develops a new treatment for a neglected disease like malaria or TB can get priority review from the Food and Drug Administration for another product they've made. If you develop a new drug for malaria, your profitable cholesterol-lowering drug could go on the market a year earlier. This priority review could be worth hundreds of millions of dollars.” The speech is at the Gates Foundation web site.
• Law: Food and Drug Administration Amendments Act of 2007 (see page 150)
• Summary: A description of the mechanism can be found at the BIO Ventures for Global Health