AbstractFifteen patients with acquired immune deficiency syndrome (AIDS) and opportunistic infection, were randomized to receive treatment with either thymostimulin (TP-1) at 1 mg/kg for 14 days then weekly for 12 weeks or placebo. The objectives of this study were to evaluate the toxicity of TP-1 in this patient population and to make observations on clinical response as measured by time to second opportunistic infection (OI) and changes in laboratory parameters of immune function. The study demonstrates that TP-1 can be administered safely. There were no differences, however, in time to second OI or overall survival between patient groups. In addition, no change in the immune function could be detected in patients receiving thymostimulin.