AEGiS-13IAC: The Swiss-Spanish Intermittent Trial (SSITT).

13th International AIDS Conference

Durban, South Africa - July 9-July 14, 2000

The Swiss-Spanish Intermittent Trial (SSITT).

Int Conf AIDS 2000 Jul 9-14; 13:(abstract no. ThOrB747)

Hirscgel B, Fagard C, Lebraz M, Tortajada C, Garcia F, Bernasconi E, Battegay M, Gunthard H, Furrer H-J, Vernazza P, Oxenius A, Phillps R, Yerly S, Gatell J, Perneger T, Erb P, Perrin L
B. Hirscgel, Hopital Cantonal, 24, rue Micheli-du-Crest, CH-1211 Geneve, Switzerland, Tel.: +41 22 372 98 12, Fax: +41 22 372 98 20, E-mail: bernard.hirschel@hcuge.ch

BACKGROUND: HIV-specific immune response (IR) weakens during HAART. Rebounds during treatment (Rx) interruption may stimulate the IR and eventually permit discontinuation of HAART.

METHODS: Patients on HAART (most of them ART-naive before HAART, without treatment failure, never on NNRTIs, with a viral load (VL)>50 copies/ml, and a CD4 count, >300/mm³) were recruited from 8 Swiss centers and in Barcelona. 4 cycles of 2 weeks' treatment (Rx) interruption and 8 wks Rx were administered; patients were excluded if VL remained >50 after each period of re-treatment. Rx will be definitively suspended at wk 40 unless VL rebounds > 5000. HIV-specific CD8 function will be measured by interferon production (Elispot) and tetramer staining.

RESULTS: On January 15, 2000, 105 patients were included, 71 M/34F, 86 stage A,12:B, 7:C. Median CD4 count before HAART: 387, median CD4 count at inclusion: 740. VL median of 96 patients at first rebound (wk 2) was 2.83 log (range >10 to 925000), and 28 patients had no rebound (VL>100). No significant differences between CD4 cells and VL were measured while comparing the second and third cycles to the first. 10 of 54 patients had a smaller rebound (difference of > 0.5 log) during the second cycle than during the first, and 6 of 23 patients had a smaller rebound during the third cycle than during the first. 5 of 75 patients were excluded at the end of the first cycle because VL remained above 50, and one of 35 at the end of the second cycle. So far, viremia eventually decreased to > 50 without changing Rx in all patients.

CONCLUSION: No clear tendency for a decrease in viral rebound during successive treatment interruptions has emerged. Immunologic investigations are ongoing. In July, information on > 300 treatment interruptions, and follow-up on > 50 patients with indefinite suspension of treatment, will be available. Treatment interruptions have not resulted in viral escape or resistance so far.

Keywords: AEGIS, Antiretroviral Therapy, Highly Active, CD4 Lymphocyte Count, Viral Load, HIV Infections, Anti-HIV Agents, HIV, Viremia, CD4-Positive T-Lymphocytes, HIV Protease Inhibitors, HIV Antibodies, Antigens, CD8, Human, immunology
000709
ThOrB747