VANCOUVER, BC--The goals of cost-effective therapy for HIV infection
are to suppress viral replication to a level that halts disease
progression, maximizes immune recovery, and limits the emergence
of drug resistance, Margaret Fischl, MD, said at the 11th International
Conference on AIDS.
New data presented at the meeting (see last month's issue, pp
1, 19, 28) offer the hope that these goals are achievable. Furthermore,
new regimens that produce durable responses could be cost effective.
But Dr. Fischl, who conducted the clinical trial that led to the
approval of the first anti-HIV drug, AZT (Retrovir), worries that
many patients will not be able to benefit from these treatment
advances due to lack of funding not only for drugs but also for
tests to monitor the disease.
Like other experts at this meeting, Dr. Fischl recommends using
plasma viral RNA measurements to guide initiation of therapy and
to monitor response to therapy. "Early treatment is likely
to achieve a greater magnitude of viral suppression and more durable
responses," she said.
Dr. Fischl also pointed out that early therapy is likely to result
in greater immunological recovery. "Even the data from the
triple-drug therapy trials suggest that there is a limit to immune
system recovery," she said. There is extensive trapping of
HIV in lymph nodes, progressive destruction of the lymph nodes,
and subsequent spillover of virus into the plasma, she said. "The
real reservoir of virus is in the lymph nodes."
The immunological damage caused by HIV infection is progressive
and not necessarily reversible, Dr. Fischl said. "It is certainly
possible to suppress virus to such low levels that one cannot
even culture virus," she noted, "but one does not necessarily
see immunologic recovery in the majority of patients treated."
This is a reason for starting HIV treatment early, while the immune
system is relatively intact. Dr. Fischl recommends that combination
antiretroviral therapy be initiated if the patient's plasma viral
RNA load is 5,000 to 10,000 copies/mL regardless of symptoms or
CD4 lymphocyte counts.
She explained that with triple-drug therapy, most patients' viral
loads can be reduced below detectable levels and maintained over
time, and that this appears to delay development of drug-resistant
strains of the virus.