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.