A Study of Trimetrexate With Leucovorin Rescue for AIDS Patients Who Are Refractory to Standard Therapies for Pneumocystis Carinii Pneumonia

To study the safety and effectiveness of trimetrexate (TMTX) plus leucovorin calcium rescue (LCV) in the treatment of Pneumocystis carinii pneumonia (PCP) in patients who have AIDS, patients who are HIV positive, or those for whom laboratory confirmation of HIV infection has not yet been established if they are at high risk for HIV infection, and who have not responded to standard treatments or who have demonstrated severe or life-threatening intolerance to both conventional therapies for PCP. The drugs trimethoprim / sulfamethoxazole (TMP / SMX) and pentamidine, usually used to treat PCP in AIDS patients, have proven ineffective in many patients and have had to be discontinued in many other patients because of severe side effects. TMTX was chosen for this trial because it was found to be very active against the PCP organism in laboratory tests and, in a preliminary trial in combination with LCV, there was a high response rate without severe toxicity. The drugs trimethoprim / sulfamethoxazole (TMP / SMX) and pentamidine, usually used to treat PCP in AIDS patients, have proven ineffective in many patients and have had to be discontinued in many other patients because of severe side effects. TMTX was chosen for this trial because it was found to be very active against the PCP organism in laboratory tests and, in a preliminary trial in combination with LCV, there was a high response rate without severe toxicity. AMENDED: 08/01/90. As of August 31, 1989, 437 patients were enrolled into uncontrolled studies of trimetrexate for PCP: 214 in TX 301/ACTG 039 (trimetrexate for patients intolerant of approved therapies) and 223 in NS 401 (trimetrexate for patients refractory to approved therapies). The analysis of overall response rate, stringently defined as having received at least 14 days of trimetrexate and being alive at follow-up 1 month after the completion of therapy, reveals 84/159 intolerant patients and 48/160 refractory patients had responded, for rates of 53 percent and 30 percent, respectively. These response rates include all individuals who received at least one dose of trimetrexate. Of the 111 patients who were ventilator-dependent at study entry, 18 completed a course of therapy and were alive a month later, for a response rate of 16 percent. All other ventilated patients died. The most common severe (grades 3 and 4) toxicities were: transaminase elevation (> 5 x normal) in 94 patients, anemia (< 7.9 g/dl) in 109, neutropenia (< 750 cells/mm3) in 58, fever (> 40 C) in 37, and thrombocytopenia (< 50000 platelets/mm3) in 27. Toxicity required discontinuation of therapy in approximately 5 percent of all patients. Original design: Patients entered in the study are given TMTX once a day for 21 days and LCV 4 times a day (every 6 hours) for 24 days. Doses are determined by body size. Both drugs are given by intravenous infusion, but LCV may be given orally after the first 10 days. Doses are adjusted if side effects, such as low white blood cell count, are too severe. During the 21-day trial, zidovudine (AZT) may not be used, because of possible increased bone marrow toxicity. AZT may be resumed as soon as the administration of TMTX and LCV has been completed. After treatment with TMTX, the patient may be treated with other drugs to prevent the recurrence of PCP at the discretion of his/her physician.