10th Conference on Retroviruses and Opportunistic Infections Boston, MA USA - February 10 -14, 2003

Conf Retroviruses Opportunistic Infect 2003 Feb 10-14;10th: abstract no. 639
M. Fischer¹, R. Hafner¹, C. Schneider¹, A. Trkola¹, B. Joos¹, H. Joller¹, B. Hirschel², R. Weber¹, H. Günthard¹ , The Swiss HIV Cohort Study^3
1Univ Hosp, Zurich, Switzerland; ²Univ Hosp, Geneva, Switzerland; and ³Switzerland

BACKGROUND: To evaluate time to viral rebound in patients (pts) undergoing repeated structured treatment interruptions (STIs).

METHODS: Fourteen (14) chronically HIV-infected pts who were enrolled in the Swiss-Spanish-Intermittent Treatment-Trial (SSITT) underwent frequent blood sampling. Pts underwent 4 cycles of 2-week (wk) STIs, followed by 8-wk retreatment with identical antiretroviral treatment (HAART) used before STI. At the 5^th cycle, treatment was stopped for a longer period. Before each new STI, viral load had to reach < 50 copies/ml. Viral load was measured during day 0 (last day on HAART), day 4, 8, and 14 during all 5 STIs.

RESULTS: During the first cycle, HIV-plasma RNA increased to >50 copies in 5 pts (range 67-88 copies/ml) at day 4; in 8 pts (> 100 copies/ml) at day 8; and in 12 pts (> 100 copies/ml) at day 14. Cumulative analysis of the frequency of detectable HIV-RNA at days 4, 8, and 14 compared to day 0 for all 5 cycles revealed 9 pts with viral load > 50 copies/ml (13 of 54 samples tested [24.1%], p = 0.14) at day 4, 11 pts (33 of 58 samples tested [56.9%] p < 0.0001) at day 8 and 12 pts (53 of 65 samples tested [81.5%], p < 0.0001) at day 14.

CONCLUSIONS: Significant viral replication can be induced during one week STIs, and may increase the risk of the emergence of drug resistance during long-term cycling. Therefore, short-term cycling strategies such as 1-wk on, 1-wk off treatment, although conceptually intriguing, should still be regarded as investigational, and should be restricted to rigorously controlled clinical trials ideally involving pts who have never failed treatment before.

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Copyright © 2003 - Foundation for Retrovirology and Human Health. Reproduction of this abstract (other than one copy for personal reference) must be cleared through the Foundation for Retrovirology and Human Health. Licensed (AIDSLINE) from National Library of Medicine.