A Pilot Study to Evaluate the Ability of Maintenance Therapy With the HIV Fusion Inhibitor T20 to Prevent Rebound of Plasma HIV RNA Following an Interruption of HAART

This study will evaluate whether a drug called T-20 can slow or prevent a rapid return of HIV in the blood when HAART (highly active antiretroviral therapy) is stopped temporarily. HAART is a multi-dose regimen that is very effective in suppressing HIV and perhaps slowing or halting progression of the viral infection towards AIDS. However, this treatment is not problem-oriented. It cannot completely rid the body of virus, and long-term therapy carries a risk of toxicity (harmful side effects). Moreover, the treatment is difficult to adhere to because of the many pills and capsules that must be taken daily. When patients stop taking HAART, their viral levels climb again. This study will see if T-20 can prolong the time it takes for HIV blood levels to rise in patients who stop HAART temporarily. The results may provide insight into possible new HAART-sparing treatments.

HIV-infected patients 18 years of age and older who have received HAART for at least 1 month may be eligible for this study. Candidates will be screened with a medical history, physical examination, blood and urine tests and possibly a chest X-ray and electrocardiogram (EKG).

Participants will receive either 100 Mg. of T-20 twice a day or 200 Mg. once a day, injected under the skin, and their normal HAART regimen for 3 days. (Patients or a caregiver will be taught how to give the T-20 injections.) On the fourth day, HAART will be stopped and all patients will receive 100 Mg. of T-20 twice a day for 6 weeks. Blood will be drawn weekly from the second to the sixth week after stopping HAART to check viral levels and CD4+ T cell counts. At the end of the 6 weeks, T-20 will be stopped and HAART will be restarted. Patients will then be evaluated once a month until their viral level is less than 50. The final clinic visit will be one month after this time.

In addition to blood draws, patients will undergo leukapheresis before beginning T-20 and possibly again when they restart HAART and at the end of the study. For this procedure, whole blood is collected through a needle placed in an arm vein, similar to donating blood. The blood circulates through a machine that separates it into its components. The white cells are then removed, and the red cells, platelets and plasma are returned to the body, either through the same needle used to draw the blood or through a second needle placed in the other arm. The white cells are used to study T cell function and levels and to detect hidden virus.