An undetectable viral load for the previous six

An undetectable viral load for the previous six months was a requirement to enter the study. Gutmann’s team monitored CD4 and HIV levels in the blood regularly throughout the study. Participants’ HIV levels in the genital tract and CSF were also measured at study entry, after 48 weeks of treatment and at the point of treatment failure.

To protect the participants, the study was designed to terminate early if six of the first 30 people in the monotherapy arm experienced treatment failure. Treatment failure was defined as having more than 400 copies of virus in the blood on two consecutive viral load tests. As six of the first 30 people in the monotherapy arm did experience treatment failure, the study was halted early, after only 60 percent of the planned number of participants had been recruited. In turn, “the focus of investigations, therefore, shifted to explaining these failures and looking for predictive factors,” the authors commented.

The average amount of time between switching to monotherapy and experiencing treatment failure was 12 weeks. CSF measures were taken upon confirmed treatment failure, usually within four weeks.

Gutmann and her colleagues found that detectable HIV levels in the CSF were associated with treatment failure. Given the study design, it isn’t possible to determine that increased viral replication in the brain actually caused treatment failure. The authors point out, however, that none of the 15 people on standard therapy—who consented to have their CSF measured at that time point—had detectable virus in the brain upon study termination, while eight of 24 people on monotherapy did have detectable virus