Finding the Right Use for Treatment Interruptions

The newly developed strategy of using interruptions in therapy, (known as "structured therapy interruptions," or STI) to stimulate HIV-specific immune responses has shown promise when used in people who began HAART immediately after becoming infected with HIV. By beginning HAART during primary infection, the immune system's HIV-specific responses are not destroyed by super high levels of the virus. Researchers are currently investigating the idea that when a person who has preserved these natural HIV-specific responses later goes off HAART therapy (with an undetectable viral load), his or her immune system will be able to maintain control of the virus without antiretroviral medications.

Eric Rosenberg, Bruce Walker, and colleagues from Harvard Medical School, published a very significant paper in the journal Nature on September 28, 2000. They reported the results of treatment interruptions in people treated with HAART within 72 hours of diagnosis of primary HIV infection. It is very important to note that the promising results reported in this study were not seen when STI was used in people who began HAART after they had been infected with HIV for any more than two months. Sixteen people were treated with HAART within 72 hours of the diagnosis of primary HIV, before HIV antibodies were detectable. The diagnosis was made by checking HIV RNA, or viral loads, in people who presented with signs and symptoms of primary HIV infection, and a history of recent possible exposure to HIV. The usual symptoms include a severe flu-like syndrome, with fever, sore throat, swollen lymph nodes, and a rash.

Immediate treatment with HAART was shown to preserve strong immunologic responses to HIV. The researchers evaluated eight people who had good virologic suppression on their initial HAART regimen (HIV RNA <50 for more than 8 months) who then had several 4-week interruptions in HAART. After each treatment interruption, there was a slower rebound in HIV RNA, or viral load, as well as improved immunologic responses to HIV. Currently, 5 of the 8 people remain off HAART, with good immunologic control of HIV levels (HIV RNA <500 copies/ml). These five have been infected for an average of 2.7 years. The authors emphasized that enhanced immunologic responses to HIV are not seen when treatment interruptions are used in people started on HAART who have chronic HIV infection, i.e. when HAART is not started at the time of primary HIV infection.

Note: Only about 70% of people have symptoms of primary HIV infection when they are first infected with HIV, and those that do are often misdiagnosed as having the flu. However, primary healthcare providers, and urgent care and emergency room providers need to be alert to this syndrome. Unless an HIV RNA is checked, the diagnosis cannot be made. In the past it was less critical (in terms of future therapy options), to make a diagnosis at the time of primary HIV infection. However, if the above data is verified (by studying larger numbers of people for longer periods of time), it may be very important to make the diagnosis of primary HIV infection in order to take advantage of this strategy. Both the general public and healthcare providers need to think carefully when someone has the symptoms described above. Providers need to take a careful history and order an HIV RNA viral load test if primary HIV infection is suspected.