The Safety and Efficacy of Clindamycin and Primaquine in the Treatment of Mild - Moderate Pneumocystis Carinii Pneumonia in Patients With AIDS

To determine the safety and effectiveness of clindamycin and primaquine in the treatment of mild Pneumocystis carinii pneumonia (PCP) in AIDS patients. As many as 80 percent of AIDS patients experience at least one episode of PCP and about one-third of these patients have a recurrence of the disease. Drugs currently used for treatment of acute PCP are toxic to the majority of AIDS patients. The combination of clindamycin and primaquine reduces the numbers of PCP organisms in laboratory tests and in animal studies. Both drugs can be given orally, concentrate in lung tissue, and have been used safely in humans for treatment of other diseases. It is possible that the combination may prove to be as good or better than standard therapy for PCP and side effects may be less. As many as 80 percent of AIDS patients experience at least one episode of PCP and about one-third of these patients have a recurrence of the disease. Drugs currently used for treatment of acute PCP are toxic to the majority of AIDS patients. The combination of clindamycin and primaquine reduces the numbers of PCP organisms in laboratory tests and in animal studies. Both drugs can be given orally, concentrate in lung tissue, and have been used safely in humans for treatment of other diseases. It is possible that the combination may prove to be as good or better than standard therapy for PCP and side effects may be less. The proposal for the first 20 patients enrolled in ACTG 044 initially called for an open-labelled, pilot study of intravenous (IV) clindamycin and primaquine therapy in patients with mild to moderate PCP. Preliminary results of the first 22 patients entered into ACTG 044 indicate that the response rate to therapy was over 90 percent. The rate of discontinuation secondary to toxic side effects was only 20 percent. Additional uncontrolled studies have shown an excellent clinical response and safety profile in another 60 patients. The protocol has been amended to provide an all oral dosing regimen. An additional 20 patients with mild PCP will be enrolled and tested with oral clindamycin and primaquine on an outpatient basis. All patients will receive clindamycin and primaquine. Total duration of therapy will be 21 days. Patients may be hospitalized at any time during the study as clinically indicated. Treatment with zidovudine may be started or resumed after completion of clindamycin / primaquine therapy. AMENDED: An additional 30 patients instead of 20 patients with mild PCP will be enrolled.