THE NEWEST weapon against Pneumocystis carinii pneumonia (PCP) is the antifolate trimetrexate glucuronate.
After nearly 8 years in development as a treatment for PCP, the drug received Food and Drug Administration (FDA) marketing approval late last month. Pharmaceutical maker US Bioscience Inc, West Conshohocken, Pa, will market it under the brand name NeuTrexin.
Approval of the drug is an important development for the 80% of AIDS patients who require treatment for PCP, says Robert Capizzi, MD, executive vice president of research and development at Bioscience.
But company officials and researchers involved in clinical trials of trimetrexate note that its main value is as a salvage medication rather than a drug of choice for PCP. It is indicated for patients who cannot tolerate the combination of trimethoprim and sulfamethoxazole (TMP/SMX).
Trimetrexate works by inhibiting dihydrofolate reductase (DHFR), the enzyme that both healthy human cells and P carinii require for metabolism and