Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0027947 (neutropenia)
 17,527 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Trimetrexate, a lipophilic, 2,4-diaminoquinazoline derivative of methotrexate, enters cells by passive diffusion rather than via a transport system. Trimetrexate has shown promising activity in animal model systems. A total of 16 patients with metastatic soft-tissue sarcoma who had received only one prior chemotherapy regimen were treated with trimetrexate (8 mg/m2 given intravenously daily for 5 days) every 3 weeks. Treatment-related toxicity included greater than or equal to grade 2 neutropenia (8/16), thrombocytopenia (3/16), mucositis (4/16) and skin rash (3/16). No partial or complete responses were observed in 15 evaluable patients (95% confidence interval for true response rate, 0-22%) Six subjects showed stabilization of disease for periods ranging from 2 to 9 months. At this dose and on this schedule, trimetrexate appears to have little activity against refractory soft-tissue sarcomas.
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PMID:Phase II trial of trimetrexate in patients with advanced soft-tissue sarcoma. 183 Feb 49

Trimetrexate (TMTX) is a potent inhibitor of dihydrofolate reductase that circumvents the transport resistance seen with methotrexate and has a wide spectrum of preclinical activity. A total of 18 patients with advanced cancer were treated in a clinical and pharmacological phase I trial with TMTX given as a continuous 5-day intravenous infusion. Neutropenia, thrombocytopenia and stomatitis were the dose-limiting toxicities at the maximum tolerated dose of 50 mg/m2 per 120 h (10 mg/m2 per day for 5 days). There was one septic death associated with neutropenia. Other toxicities were mild rash, mild nausea and transiently raised serum transminase levels. Significant relationships between the dose given and the AUC of plasma TMTX and the steady-state plasma level were established. Significant, although weak, relationships between the percentage of change in neutrophils and platelets and both the AUC and steady-state plasma level of TMTX were also observed. No objective tumour responses were seen, although six patients had stable disease. The recommended phase II dose for a continuous infusion of trimetrexate is 40 mg/m2 per 120 h.
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PMID:A phase I study of trimetrexate (NSC 352122) administered by 5-day continuous intravenous infusion. 252 92

Preclinical studies have demonstrated that trimetrexate is a potent inhibitor of dihydrofolate reductase from Pneumocystis carinii. On the basis of this evidence, this lipid-soluble antifolate was used as an antipneumocystis agent in 49 patients with the acquired immunodeficiency syndrome (AIDS) and pneumocystis pneumonia. Simultaneous treatment with the reduced folate leucovorin was used as a specific antidote to protect host tissues from the toxic effects of the antifolate without affecting the antipneumocystis action of trimetrexate. Patients were assigned to three groups and treated for 21 days: in Group I, trimetrexate with leucovorin was used as salvage therapy in patients in whom standard treatments (both pentamidine isethionate and trimethoprim-sulfamethoxazole) could not be tolerated or had failed (16 patients); in Group II, trimetrexate with leucovorin was used as initial therapy in patients with a history of sulfonamide inefficacy or intolerance (16 patients); and in Group III, trimetrexate with leucovorin plus sulfadiazine was used as initial therapy (17 patients). The response and survival rates were, respectively, 69 percent and 69 percent in Group I; 63 percent and 88 percent in Group II; and 71 percent and 77 percent in Group III. Trimetrexate therapy had minimal toxicity; transient neutropenia or thrombocytopenia occurred in 12 patients and mild elevation of serum aminotransferases in 4. We conclude that the combination of trimetrexate and leucovorin is safe and effective for the initial treatment of pneumocystis pneumonia in patients with AIDS and for the treatment of patients with intolerance or lack of response to standard therapies.
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PMID:Trimetrexate for the treatment of Pneumocystis carinii pneumonia in patients with the acquired immunodeficiency syndrome. 295 10

Trimetrexate, an investigational antifol, has been associated with marked variability in drug tolerance among patients. The agent is extensively protein bound, and hepatic biotransformation plays a major role in its elimination. In early phase II testing, nine of 15 patients who experienced life-threatening or fatal toxic effects from trimetrexate had albumin levels less than or equal to 3.5 g/dL prior to treatment. This prompted a review of the data base on 272 patients entered in phase I clinical trails. The incidence of severe or life-threatening anemia, leukopenia, neutropenia, thrombocytopenia, mucositis, and hepatic toxic effects during the first course of trimetrexate was analyzed according to dose, schedule, prior treatment, and baseline protein and albumin levels. The schedules using doses given by short infusions of 30-60 minutes daily for 5 days or weekly for 3 weeks were generally associated with higher incidence of toxic effects than the schedules using doses given every other week by short infusions or those using continuous infusion. The occurrence of leukopenia and mucositis was dose related. Patients with baseline albumin levels less than or equal to 3.5 g/dL had higher incidence of all types of severe or life-threatening toxic effects than those with albumin levels greater than or equal to 3.6 g/dL, and the differences were significant for the development of anemia, thrombocytopenia, and mucositis. Similar correlations were noted for pretreatment protein levels less than or equal to 6.0 g/dL. The small cohort of patients with leukemia experienced substantial toxic effects and tended to have low protein and albumin levels. Performance status and prior therapy did not emerge as strong predictors of severe toxic effects in the univariate analysis. Multivariate analysis confirmed that the type of cancer (leukemia vs. solid tumor), dose, schedule, and baseline albumin level were significant and independent predictors of severe and life-threatening toxic effects in the phase I patient population. Multivariate analysis including only patients with solid tumors indicated that albumin level, dose, and schedule remained significant predictors of toxic effects. Since normal liver function as reflected by bilirubin and transaminase values were a requirement for eligibility, the results suggest that albumin and protein levels may provide a more sensitive index of hepatic function. Patients with hypoalbuminemia and hypoproteinemia are at increased risk of experiencing severe or life-threatening toxic effects from trimetrexate and should be treated cautiously.
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PMID:Correlates of severe or life-threatening toxic effects from trimetrexate. 297 17

Trimetrexate is a folinic acid analogue structurally related to methotrexate, whose primary mechanism of action is believed to be inhibition of dihydrofolate reductase. This reduces the production of DNA and RNA precursors and leads to cell death. Trimetrexate is lipophilic and can passively diffuse across cell membranes including those of Pneumocystis carinii and its mammalian host. To minimise toxicity, trimetrexate must be coadministered with calcium folinate (leucovorin calcium), a reduced folate coenzyme, which is transported into, and protects, mammalian host cells but not P. carinii cells. In noncomparative trials trimetrexate was effective in the treatment of P. carinii pneumonia (PCP) in patients with AIDS who were intolerant of or refractory to cotrimoxazole (trimethoprim/sulfamethoxazole) and pentamidine treatment. In these patients, 2- to 4-week survival rates of 48 to 69% were reported. In a comparative trial in the initial therapy of PCP, trimetrexate was less effective than cotrimoxazole in moderate to severe disease as evidenced by a significantly higher failure rate. Trimetrexate was better tolerated than cotrimoxazole when used in this setting, however. Significantly fewer patients receiving trimetrexate plus calcium folinate discontinued treatment because of adverse events than did patients receiving cotrimoxazole. The most common adverse effect associated with trimetrexate is myelosuppression (neutropenia and thrombocytopenia); this is mitigated by coadministration of calcium folinate and is generally reversible upon dosage reduction or discontinuation. Other adverse effects include increases in serum aminotransferase levels, anaemia, fever, rash/pruritus, and increased alkaline phosphatase or serum creatinine levels. Further research into the use of trimetrexate, including its efficacy as prophylaxis, in combination with other agents and as an oral formulation, is needed to clearly define its role in the treatment of PCP and to identify patients most likely to benefit. Currently, trimetrexate should be considered as an alternative treatment option in immunocompromised patients with moderate to severe PCP who have not responded to or are intolerant of first-line therapy.
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PMID:Trimetrexate. A review of its pharmacodynamic and pharmacokinetic properties and therapeutic potential in the treatment of Pneumocystis carinii pneumonia. 778 90

Trimetrexate (TMTX), a lipophilic antifol, was evaluated in a Pediatric Oncology Group (POG) Phase I trial in children with refractory solid tumors. TMTX was administered intravenously daily x 5 every three weeks. Starting dose was 6.4 mg/m2/day. Dose was escalated by 20% until the maximal tolerated dose was reached. A total of 75 courses were administered to 26 children. The major toxicity was myelosuppression, of which neutropenia and thrombocytopenia were most prominent. Rash, mucositis, and transient liver enzyme elevations were infrequently seen. Responses were observed in children with brainstem glioma, neuroblastoma, and renal cell carcinoma. The recommended Phase II dose using this schedule is 9.2-11 mg/m2/day depending on how heavily the patient has been treated prior to initiating this therapy.
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PMID:Phase I trial of trimetrexate in pediatric solid tumors: a Pediatric Oncology Group study. 846 24

Trimetrexate (TMTX) is an anticancer drug with potential advantages over the more commonly used antifolate, methotrexate (MTX); however, its use has been limited by severe myelosuppression. Retroviral vectors containing mutant dihydrofolate reductase (DHFR) genes have been used to protect bone marrow cells from MTX, suggesting a similar approach could be used for TMTX. We first screened six variants of human DHFR to determine which allowed maximal TMTX resistance in fibroblasts. A variant enzyme containing a Leu-to-Tyr mutation in the 22nd codon (L22Y) was best, allowing a 100-fold increase in resistance over controls. Murine hematopoietic progenitor cells transduced with an L22Y-containing retroviral vector also showed high-level TMTX resistance in vitro. Mice reconstituted with L22Y-transduced bone marrow cells were challenged with a 5-day course of TMTX to determine whether hematopoiesis could be protected in vivo. Transfer of the L22Y vector resulted in consistent protection from TMTX-induced neutropenia and reticulocytopenia at levels that correlated with the proviral copy number in circulating leukocytes. We conclude that the L22Y vector is highly effective in protecting hematopoiesis from TMTX toxicity and may provide a means for increasing the therapeutic utility of TMTX in certain cancers.
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PMID:A gene transfer strategy for making bone marrow cells resistant to trimetrexate. 863 Apr 26

Oncology nurses play a critical role in the detection and management of adverse effects resulting from the toxicity of colorectal cancer (CRC) treatment regimens. Standard chemotherapy for CRC involves combination 5-fluorouracil plus leucovorin, a regimen with a well-characterized toxicity profile that includes abdominal cramping and diarrhea, nausea and vomiting, skin and hypersensitivity reactions, fatigue, stomatitis, neutropenia and thrombocytopenia, and alopecia. Diarrhea is the principal dose-limiting toxicity. Trimetrexate, a nonclassical antifolate, is currently being investigated in combination with 5-fluorouracil/leucovorin in phase II/III trials. In addition to the management of side effects, the psychosocial and educational needs of CRC patients require attention. The rigorous treatment schedule presents patients with multiple obstacles in daily living, significantly impacting their quality of life. The oncology nurse is vital in managing the care of CRC patients and ensuring that their physical, psychosocial, and educational needs are met. Educating patients about adverse treatment effects empowers them to manage their symptoms and enables them to alleviate serious or life-threatening treatment complications. Three case studies are provided to illustrate and reinforce nursing management strategies for hypersensitivity reactions, fatigue, and psychosocial issues related to CRC treatment.
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PMID:Nursing care strategies for the management of side effects in patients treated for colorectal cancer. 942 23