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A NEW TREATMENT FOR PNEUMOCYSTIS PNEUMONIA.

An obscure form of pneumonia only a few years ago, Pneumocystis carinii pneumonia killed more Americans during the past year than did all types of tuberculosis. Two drugs, pentamidine isethionate and trimethoprim-sulfamethoxazole, are effective in treating pneumocystis pneumonia in AIDS patients and other immunosuppressed patients; however, these treatments are often toxic to AIDS patients. A new approach combining trimetrexate and leucovorin takes advantage of the fact that P. carinii lacks a folate transport system. Trimetrexate is a potent inhibitor of P. carinii dihydrofolate reductase; but it also affects patients' cells, causing myelosuppression. Leucovorin protects the patient without compromising the toxic effect on P. carinii.

A study of 49 patients with pneumocystis pneumonia and AIDS shows that treatment with trimetrexate and leucovorin is as effective as traditional regimens. The survival rate ranged from 69 percent to 88 percent for different subgroups. However, the treatment seems to be less toxic than traditional regimens; 98 percent of patients in this study completed 21 days of therapy and remained alive, compared to 30 to 40 percent of patients in studies of other agents.

— ALK

Published in Journal Watch General Medicine October 20, 1987

Citation(s):

Allegra C J; Chabner B A; Tuazon C U et al. Trimetrexate for the treatment of Pneumocystis carinii pneumonia in patients with the acquired immunodeficiency syndrome. N Engl J Med 1987 Oct 15 317 978-985.

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