No long-term benefit from HIV treatment interruption
“Structured treatment interruption” in which highly active antiretroviral therapy (HAART) is intermittently stopped is a practice which does not appear to provide long-term benefit to patients infected with HIV.
Researchers hypothesised that this approach might boost immune responses
to control HIV infection better. Evidence from earlier research, published
in Nature in 2000, suggested that treatment interruptions worked for
patients during the earliest stages of acute infection. Viral loads in
newly infected patients remained suppressed for a median of six months
after therapy had been stopped. However, the same research group, led
by Bruce Walker of Massachusetts General Hospital, Boston, has now shown
that for most patients this effect was transient — viral load rebounded
in eight of 14 patients by one year.
The patients underwent successive treatment interruptions after an initial
treatment period of at least eight months. Treatment was restarted if
viral load exceeded 50,000 RNA copies/ml plasma on a single occasion
or 5,000 copies/ml for three consecutive weeks. Of the 14 patients in
the study, 11 achieved virologic control for at least 90 days. However,
for most patients there was a subsequent rise in viral load. Only three
patients maintained control for more than two years.
“
We … now have about five years of
follow-up on some of the patients,” says Dr Walker. “Although
we were able to use early treatment and structured treatment interruption
to boost immunity and have 11 of 14 patients control their virus, most
of the persons ultimately ‘broke through’, meaning that they
had a recurrence of viraemia.”
The researchers conclude that treatment interruptions should probably
be avoided outside the setting of controlled clinical trials. They suggest
that data from the study could be used to inform current efforts to develop
a therapeutic AIDS vaccine (PLoS Medicine 2004;1:e36). |
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