FDA Press Release - December 20, 1993
Food and Drug Administration

Trimetrexate is the first drug approved for severe PCP, although three other drugs are approved for treatment of patients with milder forms of the disease. A substantial number of PCP patients fail to respond to, or are intolerant of, these other drugs -- trimethoprim/sulfamethoxazole, injectable pentamidine and atovaquone.

Trimetrexate must be administered concurrently with leucovorin (folinic acid) to protect against potential toxic effects of tremetrexate in human cells. Patients must be monitored carefully and must continue leucovorin therapy for 72 hours past the last dose of trimetrexate.

The drug was given expanded distribution prior to approval under a "treatment IND" in February 1988 -- the first AIDS-related drug to have been granted this status. Treatment IND regulations provide a mechanism for making promising experimental drugs available to patients with certain serious or life-threatening conditions before all clinical trials required for approval have been completed.

U.S. Bioscience Inc. of West Conshohocken, Pa., manufactures trimetrexate and will market it under the name NeuTrexin.