Tacrolimus-induced bone marrow suppression

Association of long-term tacrolimus (FK506) therapy with abnormal megakaryocytosis, bone marrow fibrosis, and dyserythropoiesis

Haematopoietic abnormalities associated with tacrolimus are relatively rare with reversible pure red cell aplasia being the most common. We report for the first time, to our best knowledge, tacrolimus therapy associated with bone marrow fibrosis, abnormal megakaryocytosis, and dyserythopoiesis in a 17-year-old male treated with tacrolimus for nephrotic syndrome.

Bone marrow hypoplasia complicating tacrolimus (FK506) therapy

Tacrolimus (FK506)-induced hematological toxicity, which has rarely been reported in transplant recipients, may result in anemia episodes, reported mainly in kidney and heart transplant recipients, sporadic cases of thrombotic thrombocytopenic purpura/hemolytic uremic syndrome, red cell aplasia (4 reported cases), and generalized bone marrow suppression (only 1 reported case). We describe a case of a liver transplant recipient with pancytopenia that appeared during immunosuppressive therapy with tacrolimus. This patient suffered from progressive anemia, leukopenia with severe neutropenia, and mild thrombocytopenia; bone marrow biopsy showed hypoplasia (20% of cellularity) without dysplasia. Bone marrow recovery was made possible by suspending tacrolimus and changing to immunosuppression with cyclosporine A, despite the two drugs being very similar in their mechanism of immunosuppression. Contrary to previously reported cases (pure red cell aplasia and bone marrow hypoplasia), the recovery of hemoglobin and neutrophil values was slow after tacrolimus suspension, even though in the first month transfusions were no longer necessary.

Twelve-month evaluation of the clinical pharmacokinetics of total and free mycophenolic acid and its glucuronide metabolites in renal allograft recipients on low dose tacrolimus in combination with mycophenolate mofetil

BACKGROUND

The establishment of a rationale for therapeutic drug monitoring for mycophenolic acid (MPA) and outlining a therapeutic window remains a challenging task in renal transplantation. Furthermore, the pharmacokinetic characteristics of free and total MPA and its glucuronides depend directly or indirectly on graft function and the type of co-administered calcineurin-inhibitor.

METHODS

The authors conducted a prospective 12-month multicenter pharmacokinetic study on MPA (MPA, free MPA, free fraction MPA) and its metabolites (MPAG, Acyl-MPAG). The aim of this study was to examine the long-term pharmacokinetic characteristics of MMF when combined with tacrolimus in renal allograft recipients and to identify a possible relationship between these pharmacokinetic parameters and clinical outcome parameters.

RESULTS

They have demonstrated that in renal transplant recipients MPA, free MPA, Acyl-MPAG and MPAG have a particular pharmacokinetic profile when combined with tacrolimus which differs from the combination with CsA. They could not establish a relationship between pre-dose trough concentration of MPA and its metabolites and clinical efficacy endpoints and drug-related adverse events, except for anemia.

CONCLUSIONS

These findings suggest that trough plasma concentration monitoring of MPA and its metabolites might not provide a useful clinical tool for guiding MMF dose adjustments to avoid drug-related toxicity. More extensive pharmacokinetic measurements like area under the concentration curves might be necessary for routine therapeutic drug monitoring of MMF.

Hematologic abnormalities in liver-transplanted children during medium- to long-term follow-up

OBJECTIVE

Hematologic abnormalities as adverse effects related to immunosuppressive drugs in liver-transplanted children are rarely reported. We have observed anemia, neutropenia, and thrombocytopenia in our pediatric liver-transplant population. The aim of this study was to exclude all suspected etiologies to define the association of immunosuppressants with these abnormalities.

METHODS

Patients under 18 years old who still attend periodic controls at liver-transplant outpatient clinics were considered. Seventy patients met the inclusion criteria, 36 girls and 34 boys. Mean patient age was 5.6 years (range: 7 months to 17 years) and mean follow-up 6 years (range: 1-10 years). Medical records were reviewed beginning 1 month posttransplant. Treatment exposures, irradiation, blood product administration, and all laboratory studies were reviewed. When a hematologic abnormality was detected, we recorded the management for its resolution, the clinical response to therapy and the length of treatment.

RESULTS

Twenty-five of the 70 children suffered 26 abnormal hematologic episodes (anemia 14, neutropenia 2, thrombocytopenia 3, simultaneous anemia and neutropenia 5, and pancytopenia 2). Eleven episodes (42%) had unclear etiologies and the process of elimination suggested an association with the immunosuppressant. Switching immunosuppressant was required in four patients and dose reduction in seven.

CONCLUSIONS

Hematologic abnormalities in liver-transplanted children are common. The etiology is readily attributable to several causes. When the immunosuppressant appears to be a possible cause, the first step is dose reduction. If the hematologic abnormality persists despite dose reduction, a trial switch may be required.

Hematologic abnormalities in children and young adults receiving tacrolimus-based immunosuppression following cardiothoracic transplantation

To define the incidence, course, and etiology of hematologic abnormalities in children on tacrolimus-based immunosuppression, we reviewed records of 106 transplant patients (70 heart, 16 heart and lung, 20 double lung), 0-21 yr of age, who were transplanted at the Children's Hospital of Pittsburgh from 1989 to 1997. Fifty-four of the 106 patients (51%) developed 65 abnormal hematologic episodes (32 anemia, nine neutropenia, nine thrombocytopenia, 15 simultaneous anemia and neutropenia with or without thrombocytopenia). Common etiologies included: infections, post-transplant lymphoproliferative disease, and medications. Eleven episodes (seven anemia, one neutropenia, and three simultaneous anemia and neutropenia) had unclear etiologies and process of elimination suggested an association with tacrolimus. Interventions included filgrastim (effective in 15 of 15 patients, with resolution of neutropenia in a median of 5 days) and epoetin alfa (effective in five of 16 patients, including four of four patients with anemia possibly related to tacrolimus). Five patients (two with neutropenia and three with simultaneous neutropenia and anemia) were switched to cyclosporin A (CsA); rapid resolution occurred in four of the five patients, suggesting a possible association of the hematologic abnormalities with tacrolimus. In summary, hematologic abnormalities are common in children on tacrolimus-based immunosuppression. Most of these hematologic abnormalities are caused by common etiologies; however, a sub-population exists where tacrolimus may be the etiologic agent. Anemia and neutropenia respond to treatment with epoetin alfa and filgrastim. After thorough investigation, a trial switch to CsA may be warranted.