Discontinuing HAART may be safe for the majority of people who have effective viral suppression, as long as CD4 count remains above 200 cells/mm3, according to a study published in the 15 September 2002 edition of the Journal of Infectious Diseases.
Investigators performed a retrospective analysis of the records of 72 people who had maintained a viral load below 500 copies/mL for at least three months before stopping start.
The two main reasons reported for discontinuing HAART were side-effects and “patient preference.” The mean follow-up after stopping HAART was 45 weeks (range 12-132 weeks). The median CD4 count of people at HAART discontinuation was 554 cells/mm3 and the trial participants were classified into three groups according to the lowest point their CD4 count reached before starting HAART: below 200 cells/mm3; 200-349 cellsmm3 and above 350 cells/mm3.
On average patients lost 16 cells/mm3 per month after stopping therapy, however this masked a considerable range of experience with some people experiencing no decline or a very small drop in their CD4 count, whilst some had their CD4 count fall by over 100 cells per month.
There was a statistical association between the extent of cell loss and the increase in CD4 count whilst on therapy.
The study authors noted that: “The major predictor of the slope of CD4+ T cell decay is the number of CD4+ cells gained whilst receiving therapy, suggesting that it may be possible in many patients to determine the interval during which therapy can be safely interrupted.”
In four people, however, the interruption led to their CD4 counts falling to below 200 cells/mm3, with all of them developing an AIDS defining or other serious illness.
The authors concluded that: “Our data shows that discontinuation of antiretroviral therapy during successful virologic suppression is clinically safe for the majority of patients, provided that their CD4+ T cell counts remain >200 cells/mm3.”, with the added caveat that it was important to closely monitor patients given the risk of a rapid drop in CD4 counts and the possibility of an AIDS defining illness developing.
Reference:
Tebas P et al. Effects of prolonged discontinuation of successful antiretroviral therapy on CD4+ T cell decline in human immunodeficiency virus-infected patients: Implications for intermittent therapeutic strategies. Journal of Infectious Diseases, 186: 851-854, 2002.