Markers of response to zidovudine monotherapy among treated HIV seroconverters. Italian Seroconversion Study

The aim of the study was to evaluate indicators of response to zidovudine monotherapy in terms of progression to AIDS and death in a cohort of human immunodeficiency virus (HIV) seroconverters. From a larger observational epidemiological cohort of 1,024 HIV seroconverters we identified 315 persons on zidovudine monotherapy. In this treated cohort, age, sex, risk group, constitutional symptoms, CD4 cell count, and p24 antigen levels at initiation of treatment and 6 months later were examined separately for two outcomes, AIDS and death, using standard survival methods. The variables measured at the visit at which zidovudine monotherapy was initiated that predicted more rapid progression to AIDS were CD4 cell count (RH = 2.61); constitutional symptoms (RH = 2.56); p24 antigenaemia level (RH = 2. 17); and subsequent change in CD4 cell count (> 30% decline) contributed additional predictive information (RH = 2.70). Results were similar for mortality, and did not vary significantly by risk group. In a tested subset of patients, p24 antigenaemia was associated with high levels of plasma RNA viral load. The median number of HIV RNA copies was about 28,000 copies/ml among p24 antigen-positive individuals and about 7,700 copies/ml among participants who were persistently negative for p24 antigenaemia. CD4 cell count, symptoms and p24 antigenaemia at the start of therapy and CD4 cell decline after initiation of treatment are early indicators of disease progression in zidovudine-treated patients. The combined use of these indicators may help to better predict who will respond to zidovudine or to other antiretroviral therapies.