[31] EFFECTS OF PROLONGED DISCONTINUATION OF SUCCESSFUL ANTIRETROVIRAL THERAPY

1st International AIDS Society Conference on HIV Pathogenesis and Treatment

Buenos Aires, Argentina - July 8-11, 2001

[TITLE:] EFFECTS OF PROLONGED DISCONTINUATION OF SUCCESSFUL ANTIRETROVIRAL THERAPY

[AUTHOR(S):] Tebas P, Henry K, Mondy K, Deeks S, Valdez H, Cohen C, Powderly W
Washington University, St. Louis, Missouri, USA

IAS Conf HIV Pathog Treat 2001 Jul 8-11;1st: Abstract No. 31

[ABSTRACT:] Introduction: The use of "pulses" of HAART, initiated and discontinued at specific CD4 thresholds is a potential alternative strategy to the use of "continuous" therapy.

Methods: We looked at the rate of decay of the CD4 cell count in patients who discontinued antiretroviral therapy for at least 12 weeks after being fully suppressed with HAART, in four clinical practices across the US.

Results: 72 subjects (64% males, 35 + 1 yr of age), with a median nadir CD4 before initiating therapy of 272 cells/mm³ (IQR 77-418) and a baseline VL was 108,146 HIV RNA copies/ml discontinued HAART while having an undetectable VL for a median of 36 weeks (IQR 18-87). The most frequent reasons to discontinue therapy were patient preference and drug toxicity. CD4 count at the time of stop was 571 cells/mm³ (IQR 363-760). Mean follow up after discontinuation was 45 weeks (range 12 to 132 w). Mean CD4 decay was 16 + 5 cells/month. The slope of the CD4 decay inversely correlated with the increase of CD4 on therapy (r = -0.28, p=0.02), and the duration of undetectability (r=-0.25, p=0.04). Using multiple stepwise regression only the increase of CD4 while on therapy remained significant (p=0.02). CD4 decay did not correlate with nadir CD4 cells, baseline VL, type of HAART (PI based vs others), CD4 at the time of stop or gender. Eleven patients restarted therapy and reached an undetectable viral load again, two of them subsequently failed virologically. AIDS events occurred in 4 patients whose CD4 dropped below 200 and did not restart therapy (sepsis, wasting, 2 PCP).

Conclusions: CD4 cells counts decline progressively after discontinuing successful antiretroviral therapy. Most of the patients remained asymptomatic (if CD4 >200). Eleven subjects that restarted therapy reached undetectability again, suggesting that virologic resistance does not appear. Strategies that administer therapy intermittently, with prolong periods of treatment interruption deserve further evaluation.

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