Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:2.1.1.69 (BMT)
 2,655 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Tacrolimus (FK506) is a macrolide lactone effective in the control of graft-versus-host disease (GVHD). An interaction between high-dose methotrexate and a macrolide antibiotic (pristinamycin) leading to prolonged methotrexate exposure has been described. Because a randomized prospective trial comparing tacrolimus with cyclosporine (both in combination with methotrexate) following allogeneic BMT showed the tacrolimus plus methotrexate regimen to be more effective in prevention of GVHD, we assessed methotrexate pharmacokinetics in a subgroup of the participants of this trial to evaluate the possibility that an interaction of FK506 and methotrexate was the explanation for the clinical findings. Mean and median methotrexate levels at various time-points after the day 1 and 6 methotrexate doses were comparable in the tacrolimus and cyclosporine cohorts and were elevated in only three of 70 study patients. Area under the curve (AUC) concentrations were also similar after the day 1 and 6 methotrexate doses. Thus, no significant interaction between tacrolimus and methotrexate is apparent and the differences in efficacy between tacrolimus and cyclosporine are unlikely to be attributable to pharmacologic interactions with methotrexate.
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PMID:Lack of interaction between tacrolimus (FK506) and methotrexate in bone marrow transplant recipients. 923 56

The pharmacokinetics of tacrolimus have been studied in healthy volunteers and in adults undergoing bone marrow transplantation. However, there is little information on the pharmacokinetics of tacrolimus in children undergoing BMT. We studied pharmacokinetics of tacrolimus in seven patients (age 8-17 years) undergoing allogeneic stem cell transplantation. Four patients received matched unrelated donor (MUD) transplants, two underwent HLA-matched related donor transplants, and one underwent an umbilical cord blood donor transplant. All patients received tacrolimus by continuous infusion at 0.03-0.04 mg/kg/day beginning on the day prior to transplant. Tacrolimus whole blood concentrations were monitored by microparticle enzyme immunoassay. Our goal was to maintain a blood tacrolimus level of 10-20 microg/ml. Once patients were tolerating oral medications, tacrolimus infusion was converted to oral dosing using a 4:1 conversion. Dose of tacrolimus and resulting tacrolimus concentrations were recorded and the total body clearance of tacrolimus was calculated retrospectively. The mean clearance, based on first steady-state tacrolimus concentrations necessary for achieving a therapeutic level (10-20 microg/ml), was 108.1 ml/h/kg (range 79.7-142.0 ml/h/kg), greater than that reported in adult BMT patients (71 +/- 34 ml/h/kg). The average dose required to achieve that therapeutic range was 0.0354 mg/kg/day as an intravenous continuous infusion. Over the entire course of intravenous tacrolimus, mean clearance was 97.0 ml/h/kg (range 33.4-153.3 ml/h/kg). In six of the seven patients, clearance values dropped after 2-4 weeks of therapy by an average of 32.5 ml/h/kg. In two patients, sharp drops in clearance were temporally related to changes in liver function tests. Three of the seven patients died of severe acute GVHD; all these had undergone matched unrelated donor transplantation, and two of these three had initial clearance levels over 120 ml/h/kg. Thus, children appear to have more rapid tacrolimus clearance than adults and may need to begin therapy earlier in order to obtain stable and optimal levels. More studies are needed to confirm these preliminary results.
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PMID:Increased clearance of tacrolimus in children: need for higher doses and earlier initiation prior to bone marrow transplantation. 1062 42

Microangiopathic hemolytic anemia (MAHA) is a well-described complication of stem cell transplantation. Plasmapheresis is one modality utilized as therapy for patients who develop this complication. However, plasmapheresis may alter whole blood levels of certain medications and its effect on tacrolimus in bone marrow transplant patients is unknown. Because tacrolimus has a narrow therapeutic range, the effect of plasmapheresis on whole blood concentrations would be important to know. We report three allogeneic BMT patients who were receiving tacrolimus as acute GVHD therapy while undergoing plasmapheresis for MAHA. Tacrolimus levels seemed unaffected by plasmapheresis in these patients.
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PMID:Blood tacrolimus concentrations in bone marrow transplant patients undergoing plasmapheresis. 1072 90

Tacrolimus (FK) and cyclosporine (CsA) have been shown to be effective in the prophylaxis of graft-versus-host disease (GVHD). However, no comparative studies have yet been conducted to examine the efficacy of FK/methotrexate (MTX) and CsA/MTX in patients with severe aplastic anemia (SAA) given unrelated donor bone marrow transplantation (U-BMT). We used matched-pair analysis to compare FK/MTX with CsA/MTX in patients with SAA who received U-BMT through the Japan Marrow Donor Program. Forty-seven pairs could be matched exactly for recipient age and conditioning regimens. Forty-five patients achieved engraftment in the FK group and 42 patients in the CsA group. The probability of grade II-IV acute GVHD (aGVHD) was 28.9% in the FK group and 32.6% in the CsA group (P=.558). The probability of chronic GVHD (cGVHD) was 13.3% in the FK group and 36.0% in the CsA group (P=.104). The 5-year survival rate was 82.8% in the FK group and 49.5% in the CsA group (P=.012). The study shows the superiority of FK/MTX over CsA/MTX in overall survival because of the lower incidence of transplantation-related deaths. A prospective randomized study comparing FK/MTX and CsA/MTX is warranted.
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PMID:Tacrolimus/Methotrexate versus cyclosporine/methotrexate as graft-versus-host disease prophylaxis in patients with severe aplastic anemia who received bone marrow transplantation from unrelated donors: results of matched pair analysis. 1989 85