290   Successful Interruption of Antiretroviral Therapy (ARVT) in Patients with Primary HIV Infection (PHI).

P. Hermans*¹, K. Kabeya¹, F. Van Wanzeele², C. Verhofstede², and N. Clumeck¹.
¹C.H.U. Saint-Pierre, Brussels—U.Z. and²Gent, Belgium.

Background and Methods:10 patients (p) treated for PHI consecutively discontinued ARTV of their own will when viral load (VL) remained undetectable (<400 in 4 cases, <50 copies/ml in 6). These p were followed prospectively in order to restart ARVT if VL rebounded and remained at more than 10000 copies/ml. ARVT was given within 2 to 5.5 months after primary HIV-1 infection, defined as follows: clinical symptoms of acute seroconversion or high-risk behavior with a negative test within the previous 6 months and either a positive p24 antigen or plasma viral load (VL), or either an incomplete Western blot with less than 4 bands or a positive ELISA test with a negative result in the previous 6 months.

Results:The duration of ARVT varied from 12 to 40 months. When stopping ARVT, plasma HIV-1 VL was undetectable for 7 to 35 months. The md follow-up period after ARVT discontinuation was 17.5 months (6—48). Four out of 10 p still remain off therapy. Three p have an undetectable VL<50 copies/ml after 18, 20 and 40 months while the fourth p had a transient rebound at week 4 (VL = 4.3 log₁₀) before a spontaneous decline to reach <500 copies/ml at week 12. When comparing non-rebounders versus rebounders, no statistical differences were noted for protease inhibitor-containing regimens (2 of the non-rebounders were on ZDV + ddI), duration of the VL suppression, CD4⁺cells or CD4⁺/CD8⁺ratio. In contrast, a lower VL at baseline (1.9 to 4.2 versus 4.2 to 6.9 log₁₀copies/ml) and normalized values of activated CD3⁺CD8⁺DR⁺cells at the time of stopping ARVT were found in the non-rebounders. The patients who restarted ARVT showed a dramatic decline of their VL and reached less than 50 copies/ml.

Conclusions:The results of this limited study suggest that some patients who are rapidly treated after PHI may safely interrupt their ARVT for a prolonged period of time and are able to contain viral replication. The proportion of these patients (40%) in our early treated population is higher than the spontaneous rate of patients achieving undetectable VL at their set point without therapy.