Aerosolized pentamidine for prophylaxis against Pneumocystis carinii pneumonia: the San Francisco Community Prophylaxis Trial

The most frequent cause of death among patients infected with HIV (human immunodeficiency virus, the agent associated with AIDS) is Pneumocystis carinii pneumonia (PCP). Although certain drugs prevent this disease in some AIDS patients and individuals whose immune systems are compromised by other disorders, HIV-infected people cannot tolerate these medications on a long-term basis. An agent that shows promise in this regard is aerosolized pentamidine; a report of a controlled, randomized trial of this drug is presented. Three dosages of aerosolized pentamidine (30 milligrams every two weeks, 150 milligrams every two weeks, or 300 milligrams every four weeks) were administered to 408 patients at 12 treatment centers in the San Francisco Bay area. The majority of patients (237) had one prior episode of PCP; other groups included patients with Kaposi's sarcoma (an AIDS-related condition) who had never had PCP (55), and patients with AIDS or AIDS-related complex who had never had PCP or Kaposi's sarcoma (116). Patients were followed from their first treatment on or near July 1, 1987 until their death or December 31, 1988. The results revealed that the number of PCP episodes was lowest for patients who received the 300 milligram dose of aerosolized pentamidine (8 episodes), and that this number differed significantly from the number of PCP episodes among patients who were given the 30 milligram dose (22 episodes). Although the difference between the 150 milligram and 300 milligram doses was not significant, the lower dose was less effective when compared with the 30 milligram dose of aerosolized pentamidine. Patients who began the study within three months of a previous episode of PCP had less chance of having another episode than those who started later. Participants who had never taken zidovudine (a drug for treating AIDS) had higher mortality than those who had taken it, and zidovudine itself had an independent preventive effect on PCP. Those with a previous history of PCP and CD4 cell counts (a type of T cell) below 200 per cubic millimeter had the highest risk of contracting PCP again. Overall, aerosolized pentamidine at certain doses was an effective prophylactic treatment for preventing PCP in high-risk HIV-infected people. The most effective therapeutic regimen included zidovudine. (Consumer Summary produced by Reliance Medical Information, Inc.)