Those who experience virologic failure when taking a first-line ritonavir-boosted protease inhibitor (PI) to treat HIV may be better off staying on that regimen, aidsmap reports. Publishing their findings in Clinical Infectious Diseases, researchers conducted a retrospective analysis of 209 participants in three different AIDS Clinical Trials Group studies, all of whom experienced virologic failure while taking a first-line ritonavir-boosted PI plus two reverse transcriptase inhibitors (NRTIs) and who participated in at least 24 weeks of follow-up after the virologic failure.

Just one of the participants' virus developed a major PI-related mutation. Sixty-six percent of the participants continued on the same drug regimen following the virologic failure. The rate of viral suppression was essentially the same at 24 weeks between those who stayed on the same drug regimen and those who switched: a respective 64 percent and 72 percent, a difference that was not statistically significant, meaning it could have occurred by chance.

Those who continued on the same regimen boasted lower resistance to NRTIs and an average of 275 CD4s, compared with 213 cells among those who switched.

Among those who stayed the course on their regimens, factors that were linked to subsequent full virologic suppression included achieving a viral load below 400 before virologic failure, having a viral load below 10,000 at virologic failure and maintaining perfect drug adherence following virologic failure. For those who switched meds, there was a link between achieving a viral load below 400 before the virologic failure and having a fully suppressed viral load 24 weeks later.

The researchers concluded that for those who fail a first-line ritonavir-boosted PI regimen who have little or no drug resistance, staying on those same meds is a “reasonable approach.” They also noted that improving adherence is key to doing well on treatment following virologic failure.

To read the aidsmap story, click here.

To read the study abstract, click here.