- Have ended treatment for acute Pneumocystis carinii pneumonia (PCP) at least 2 weeks before study entry. For patients with 2 months or less experience with AZT, PCP infection will be the single and only AIDS-defining infection and must have been within 120 days of study entry. Per amendment, other AIDS-defining conditions are allowed in the 8 weeks prior to study entry (for patients in the AZT stratum).Only one episode of PCP is permitted unless patient has > 2 months AZT experience in which case > 1 prior episode of PCP infection is allowed.