People who switched from a protease inhibitor (PI) to Isentress (raltegravir) did well regardless of whether they switched to a once-daily or twice-daily dose of the drug, according to a study presented at the 49th Interscience Conference on Antimicrobial Agents and Chemotherapy (ICAAC) in San Francisco and reported by the National AIDS Treatment Advocacy Project (NATAP).

Isentress is currently the only approved drug in a class of HIV drugs called integrase inhibitors. It is a potent drug that is approved for twice-daily use in both people who are heavily treatment experienced and those who are starting treatment for the first time.

To determine whether Isentress could be used twice daily, researchers conducted a small pilot study involving 125 people who were currently stable on a regimen that included a PI. Sixty-three people who had been taking a once-daily PI exchanged the PI for once-daily Isentress, while 62 people who had been taking a twice-daily PI switched to twice-daily Isentress.

Though the two groups were similar in many respects, people in the once-daily group were somewhat older, were more than twice as likely to also be infected with hepatitis C virus (HCV) and had higher bilirubin levels.

During an average follow-up of 15 months, four people virologically failed in the twice-daily group and one failed in the once-daily group. CD4 levels were the same in both groups. Safety and tolerability were essentially the same regardless of the Isentress dosing schedule; however, there was a trend toward improved quality of life in the once-daily group.