Interrupting HIV Treatment: Can It Be Done?
Feb. 4, 2000 (San Francisco) -- While coming off toxic AIDS therapies for
"drug holidays" is popular with patients, and some have had spectacular
success, the approach has yet to prove itself as a method of boosting the
body's natural immune system. At the very least, the results of these
experiments are mixed. In several presentations here this week at an HIV
conference, researchers showed what was gained, and lost, when patients
In what is apparently the largest study of drug interruption to date,
Bernard Hirschel, MD, of University Hospital in Geneva, looked at 120 patients
who were well controlled on what is considered the standard treatment today,
highly active anti-retroviral therapy (HAART). Treatment was stopped for two
weeks and restarted for eight weeks in four different cycles. About 70% of the
patients experienced a rebound of the virus, but it was quickly brought under
The question remaining is, did anyone show an improvement in immune response
as a result of the interruption? Hirschel says there were some modest jumps
after the second drug-pause, but no clear pattern. Since the immune
measurements were done in a test tube, it's not clear what actual impact the
interruptions had on the disease. However, Hirschel says CD4 white blood cells,
which orchestrate the overall immune response, bounced back, but other parts of
the immune system did not. That was a disappointment for researchers.
"The likely best outcome is we identify a subgroup of patients where you
can stop treatment and they do well for a long time," Hirschel tells
It may also be possible to model a vaccine from knowledge gained during
these drug holidays. "Then you can ask, is it really necessary to interrupt
treatment to get this immune response? Maybe you can get a therapeutic vaccine
that mimics the immune response, and then you don't need to interrupt,"
However, another study from the University of California, San Francisco
indicated that a 12-week interruption cost patients precious CD4 cells, and it
took about a year to get them back. The research also shows that in most of the
18 patients, HIV reverted to its wild state when it wasn't being challenged by
drugs -- a measure of the virus' adaptability, and not a good state for the
On the other hand, yet another small study presented at the meeting observed
a jump in all crucial immune responses aimed at HIV. Still, many researchers
are skeptical of interrupting treatment unless patients simply can't tolerate
"When people talk about it being strategic, strategic therapeutic
interruption's an oxymoron until you actually prove it's strategic. ... It's
something that is more an experiment in biology than a treatment strategy,"
Robert Schooley, MD, tells WebMD. Schooley, head of the infectious disease
program at the University of Colorado Health Sciences Center, says at least
it's reassuring that those who do interrupt their treatment can get back on
board without long-term damage.
- It's not clear whether interrupting HIV treatment allows a patient's immune
system to rebound.
- Treatment interruption research can offer insight into developing vaccines
as well as show the best ways to bolster a patient's compromised immune
- Observers note the research suggests patients can rest from treatment
without doing long-term harm.