| Autor: |
M, Hum, J S, Holcenberg, I, Tkaczewski, J W, Weaver, J, Wilson, B A, Kamen |
| Rok vydání: |
1998 |
| Předmět: |
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| Zdroj: |
Clinical cancer research : an official journal of the American Association for Cancer Research. 4(12) |
| ISSN: |
1078-0432 |
| Popis: |
Our objective was to find the minimum dose of leucovorin (LV; 5-formyltetrahydrofolate) needed to potentially provide selective protection of normal tissue in patients with tumors resistant to methotrexate (MTX) by virtue of transport during prolonged therapy with high-dose trimetrexate (TMTX). Based upon the known daily requirement for folate, that tumors are often resistant to methotrexate via a transport-based mechanism, and that large doses of trimetrexate can be given with large doses of leucovorin for the treatment of patients with Pneumocystis carinii, a protocol was designed to find the minimum LV dose required to allow the administration of large doses of TMTX. Patients were treated in 28-day cycles consisting of 14 consecutive days of oral TMTX (45 mg/m2 every 12 h), followed by 14 days of rest. The dose of concurrent LV was started at 5 mg/m2 twice daily. Cohorts of patients received successive half doses of LV so long as three consecutive patients had less than or equal to grade 3 toxicity. Ten patients received 29 courses of therapy. The most common toxicities encountered were thrombocytopenia (38%), mucositis (14%), and neutropenia (10%). At a LV dose of 2.5 mg/m2, toxicities were consistently limited to less than or equal to grade 3 and only one episode of grade 4 hematological toxicity. Although there was marked interpatient variability, the minimally effective LV dose for selective protection seems to be 2.5 mg/m2. If tumors are resistant to methotrexate because of decreased transport of drug (and also folate), then the same pharmacological principle used to develop TMTX/LV for the treatment of P. carinii may be applied to treatment of some patients with cancer. |
| Databáze: |
OpenAIRE |
| Externí odkaz: |
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