Recombinant human erythropoietin treatment of anemia in renal transplant patients

mTOR Inhibitors and Their Secondary Effects in Cardiac Trasplant Recipients: A Descriptive Study

BACKGROUND

Mammalian target of rapamycin (mTOR) inhibitors are relatively new drugs in the field of cardiac transplantation (HT), hence the need for further study of their secondary effects. We described the nature and incidence of secondary effects of these drugs in a group of HT recipients.

PATIENTS AND METHODS

We studied 23 HT recipients aged 52 +/- 9 years (Male: 91%, body mass index: 27 +/- 3.7, ischemic cardiopathy: 52%, dilated cardiomyopathy: 39%) who were started on an mTOR inhibitor (everolimus: 65%, sirolimus: 35%) as part of their treatment. We have described the secondary effects detected during a follow-up period of 10.7 +/- 6 months.

RESULTS

The reasons for starting the drug were renal impairment (65%), tumors (26%), and others (8%). During follow-up, 17% of patients required a dose reduction and 12% required drug withdrawal: edemas: 4%, recurrent infection: 4%, and hemolytic-uremic syndrome: 4%. Drug-attributable edemas presented in 26% of patients. Thirty nine percent suffered an infection that required hospital admission, 89% of which were lung and all bacterial two patients died due to the infection). The mean time to first infection was 5 +/- 6 months. In patients who had a treatment change due to tumors, 50% experienced improvement. We did not detect alterations in cholesterol, triglycerides, creatinine, or leukocytes. There was a nonsignificant trend toward decreased hemoglobin and platelet levels (P = .07 and P = .056, respectively).

CONCLUSIONS

Lung infection was the principal complication among our patients treated with mTOR inhibitors. A large percentage required dose reduction (17%) and even drug withdrawal (12%) due to secondary effects.

A retrospective assessment of pre-treatment variables on the response to darbepoetin alfa after renal transplantation

This retrospective review assesses the efficacy of darbepoetin alfa for treating anemia after renal transplantation. Patients were evaluated over a 12-week period, and efficacy was based on achieving hemoglobin >12 g/dL. Thirty-six patients were analyzed (53% male, 53% cadaveric allografts, median age 42.5 years). Baseline creatinine clearance ranged from approximately 15 to >100 mL/min. Most patients initiated darbepoetin alfa <3 months (50%) or >12 months (44%) after transplantation, 19% were previously receiving recombinant human erythropoietin (rHuEPO), and 47% were on concomitant ACE inhibitors. The majority of patients received either tacrolimus- (53%) or cyclosporine- (44%) based immunosuppression. Overall, 29 (81%) patients achieved the hemoglobin target with a mean time to response of 4.4 weeks. Neither the time to anemia onset, previous rHuEPO therapy, concomitant ACE inhibitor, allograft source, immunosuppressive regimen, nor degree of renal function affected the proportion of patients achieving the hemoglobin target, time to response or darbepoetin alfa dose requirement. Patients with anemia >12 months post-transplantation or on concomitant ACE inhibitors required a significantly longer duration of therapy. No adverse events associated with darbepoetin alfa therapy were detected. These results demonstrate that darbepoetin alfa is a safe and effective treatment for anemia in renal transplant recipients.

Azathioprine-induced pure red cell aplasia: case report and review

The major adverse effect of azathioprine is its myelotoxicity, with leukocytes being affected more commonly than the other bone marrow elements. Although megaloblastic change is frequent, reportedly seen in 16% to 82% of bone marrow aspirates, long-term use of azathioprine rarely causes severe anemia. We report a case of refractory pure red cell aplasia resulting from long-term use of azathioprine in a renal transplant recipient and examine the possible underlying mechanisms. There was no response to dose reduction or to erythropoietin administration. However, there was immediate recovery after complete drug withdrawal. A review of the literature revealed that only ten cases of azathioprine-induced red cell aplasia have so far been described, all in transplant recipients.

Anemia in children after transplantation: etiology and the effect of immunosuppressive therapy on erythropoiesis

Anemia in children after renal transplantation is more common than previously appreciated. Multiple factors appear to play roles in the development of post-transplant anemia, the most common of which is absolute and/or functional iron deficiency anemia. Most experts recommend that iron limited anemias in transplant patients should be diagnosed using the same criteria as for chronic renal failure patients. Serum erythropoietin (EPO) levels are expected to normalize after a successful renal transplantation with a normal kidney function, yet both EPO deficiency and resistance have been reported. While no large controlled trials comparing the effect of different immunosuppressive agents on erythropoiesis after transplantation have been performed, generalized bone marrow suppression attributable to azathioprine (AZA), mycophenolate mofetil (MMF), tacrolimus, antithymocyte preparations has been reported. Pure red cell aplasia (PRCA) occurs rarely after transplantation and is characterized by the selective suppression of erythroid cells in the bone marrow. PRCA has been reported with the use of AZA, MMF, tacrolimus, angiotensin converting enzyme inhibitors (ACEI), but not with cyclosporine (CSA) use. Post-transplant hemolytic uremic syndrome has been reported with orthoclone anti T-cell antibody (OKT3), CSA and tacrolimus therapy. Viral infections including cytomegalovirus, Epstein-Barr virus and human parvovirus B19 have been reported to cause generalized marrow suppression. Management of severe anemia associated with immunosuppressive drugs generally requires lowering the dose, drug substitution or, when possible, discontinuation of the drug. Because this topic has been incompletely studied, our recommendation as to the best immunosuppressive protocol after renal transplantation remains largely dependent on the clinical response of the individual patient.

Erythropoietin and renal transplantation

The advent of erythropoietin (rHuEPO) has revolutionized the treatment of anemia in end-stage renal disease. While many studies indicate beneficial effects of rHuEPO in hemodialysis, peritoneal dialysis and predialysis patients, the impact of the drug in renal transplantation is less clear. Treatment with rHuEPO may reduce the degree of allosensitization produced by random blood transfusion while still allowing the possibility of the transplant survival benefit derived from deliberate transfusion. Recovery from anemia post-transplantation is hastened by treatment with rHuEPO, while patients with failing allografts respond to rHuEPO in a fashion similar to dialysis patients, despite the concomitant use of immunosuppressives. The erythropoietic response to rHuEPO is abrogated during episodes of acute rejection, and restored when successful treatment of rejection has occurred. Iron therapy is a critical factor for support of erythropoiesis and prevention of absolute iron deficiency posttransplantation. In patients presenting for renal transplant, the balance of evidence suggests that there is no increase in the rate of delayed graft function, graft loss or vascular thrombosis for patients who had received prior rHuEPO therapy.