Amprenavir (APV) is the newest FDA-approved protease inhibitor, and like most drugs of this class it has shown good activity against HIV. It also has the advantage of requiring only twice-daily dosing. However, even less-frequent dosing, such as once a day, may help some people adhere to their medication schedule more easily, and lead to better outcomes. Also, the fewer the number of pills required per dose, the easier it is for most people. Amprenavir usually needs to be taken as 8 pills twice daily.

This abstract reports on the development of a compound related to APV, but with better solubility in water. In early studies it shows good blood levels and low toxicity. The greater water solubility may allow this compound to be given in substantially fewer pills per dose than APV. Further studies are ongoing to develop this drug for use against HIV.