A recent study reported by AIDSmap has found that some people who have developed drug resistance to the protease inhibitor (PI) Lexiva (fosamprenavir) may have a reduced benefit from another PI, Prezista (darunavir).
The study, conducted by Yumi Mitsuya, BS, from Stanford University and colleagues, looked for mutations associated with resistance to Prezista in HIV samples taken from almost 4,000 people who had been treated with a PI. Between 96 and 99 percent of the patients had fewer than three Prezista resistance mutations, meaning that they had a 50 percent chance of having an undetectable viral load after 24 weeks of treatment using Prezista. Those with three or more mutations are less likely to respond favorably to it.
The researchers found that two groups—those who had previously used more protease inhibitors and those who’d used only Lexiva—were more likely to have three or more resistance mutations to Prezista.
