A new class of HIV drug is in trial in the United States. Doctors have noticed that patients on a retroviral “cocktail” often develop resistance to the drugs. This new class of drugs attacks the virus in a novel way, and researchers are hoping that it will be an effective weapon against HIV.

The drug, called PA-457, attacks the virus’ ability to produce capsid protein. The capsid is a conical membrane which protects the viral RNA genetic material.