SERUM P24 ANTIGEN LEVEL AS AN INTERMEDIATE END-POINT IN CLINICAL-TRIALS OF ZIDOVUDINE IN PEOPLE INFECTED WITH HUMAN-IMMUNODEFICIENCY-VIRUS TYPE-1

Serum p24 antigen levels were examined in subjects from three clinical trials of zidovudine to determine whether the pattern of change in se rum p24 antigen during the first 8-16 weeks of therapy was associated with human immunodeficiency virus type 1 (HIV-1) disease progression o r death. Among 406 patients with AIDS and a first episode of Pneumocys tis carinii pneumonia, 65% had measurable pretreatment concentrations of serum p24 antigen (greater than or equal to 10 pg/mL). Changes duri ng treatment were not associated with reduced mortality. In 637 mildly symptomatic patients, 24% had measurable concentrations, and changes were marginally associated with increased time until more advanced dis ease. Among 683 asymptomatic patients, 18% had measurable concentratio ns, and changes were not associated with increased time until progress ion. Despite the small number of clinical events and the low rate of s erum p24 antigen positivity in the latter two studies, pretreatment se rum p24 antigen levels were predictive of clinical outcome; subsequent measurements appear to be of limited use in evaluating zidovudine the rapy.