April 6, 2011
Results from a phase 2 study were released in the March 27 issue of AIDS on the experimental “quad” pill: a full regimen of two NRTIs (tenofovir and emtricitabine), a new integrase inhibitor (elvitegravir) and a new boosting drug (cobicistat) all in one pill. The study compared the side effects and control of HIV of the quad pill against the current one-pill regimen, Atripla (tenofovir + emtricitabine + efavirenz).
People were randomly given either the quad pill (48 total) or Atripla (23 total) for 48 weeks. Although those on the quad pill showed a faster decrease to undetectable viral loads, both regimens showed about equal control of HIV: 90% on the quad pill and 83% on Atripla had undetectable HIV at both 24 and 48 weeks.
However, where they differed significantly was in side effects. Of those who took the quad pill, 17% had central nervous system side effects (such as dizziness and sleep problems) compared to 26% on Atripla. As for psychiatric issues, such as trouble concentrating or strange thoughts, only 10% on the quad pill showed these side effects contrasted with 44% on Atripla.
Slight decreases in kidney function occurred within the first few weeks in those who took the quad pill. This decline remained within normal ranges and did not persist over the study period. No one quit the study due to kidney problems.
So far, the quad pill appears to be equal to Atripla in its control of HIV over 48 weeks, which could eventually help to position itself as Atripla’s competitor. As well, the quad appears to cause far fewer side effects, likely due to the efavirenz in Atripla. And though kidney function declined slightly in the first few weeks on the quad pill, it did not persist and stayed within a normal range. The pill will now move onto larger phase 3 study.