Tuberculosis after conversion from azathioprine to mycophenolate mofetil in a long-term renal transplant recipient

We report the third case in the literature of a patient with a long-lasting renal allograft who experienced tuberculosis just after the switch from azathioprine to mycophenolate mofetil. The switch was likely responsible for the reactivation of dormant tuberculosis; prophylactic antituberculous treatment should be considered in cases of such a therapeutic change.     

Improvement in long-term graft survival in cadaveric renal transplant recipients treated with mycophenolate mofetil

Though mycophenolate mofetil has markedly reduced the incidence of acute rejection in renal transplantation, a significant improvement in graft survival has been more difficult to demonstrate. This retrospective study compares an historical control group of 210 consecutive renal transplant patients, who had received ATG induction associated with cyclosporin, prednisolone and azathioprine, with 187 patients receiving mycophenolate instead of azathioprine. The incidence of acute rejection was decreased with mycophenolate. In rejection-free patients, the 3-year graft survival rates were equivalent. In contrast, graft survival at 3 years improved significantly for patients who experienced a rejection crisis and remained under the initial triple drug regimen with mycophenolate compared to the patients of the historical group who were kept on azathioprine after a rejection episode. In conclusion, mycophenolate mofetil is not only able to reduce the incidence of acute rejection but could also improve the prognostic significance of acute rejection crises.     

Tacrolimus plus low-dose mycophenolate mofetil in renal transplant recipients: better 2-year graft and patient survival than with a higher mycophenolate mofetil dose

OBJECTIVES: Mycophenolate mofetil (MMF) has become more widely prescribed in recent years, but its adverse effects on the gastrointestinal system and bone marrow restrict its use in certain settings. The aim of this study was to compare the demographic features and clinical data for 173 renal transplant recipients who received tacrolimus (TAC) plus 1 g/d MMF (group I, n = 112) versus TAC plus 2 g/d MMF (group II, n = 61 patients) over a 2-year period. Each patient received similar TAC doses. METHODS: We compared demographic data and clinical data for each case: acute rejection (AR) episodes, chronic rejection (CR) episodes, death, graft loss, development of posttransplantation diabetes mellitus (PTDM), and posttransplantation hypertension rates. RESULTS: Demographic features were similar. There were also no significant differences between groups I and II with respect to number of AR episodes (17/112 vs 12/61, respectively), number of CR episodes (4/112 vs 1/61, respectively), PTDM, and hypertension rate (P > .05). Kaplan-Meier survival analysis revealed 2-year graft survival rates of 94% in group I versus 83% in group II. The corresponding 2-year patient survival rates were 100% in group I versus 91% in group II. The graft survival and patient survival rates in group I were significantly higher than those in group II (log-rank 0.005 and 0.001, respectively). CONCLUSIONS: The 2-year graft and patient survival rates for the renal transplant recipients in this study suggest that the combination of a full TAC dose with 1 g/d MMF is a better choice than 2 g/d MMF.     

Cyclosporine and mycophenolate mofetil 48 hours before renal transplantation enables the use of low cyclosporine doses and achieves better graft function

Reducing calcineurin-inhibitor induced nephrotoxicity and simultaneously avoiding long-term side effects are desirable goals in renal transplantation. We examined the hypothesis that administration of cyclosporine and mycophenolate mofetil (MMF) 48 hours before renal transplantation allows reduction in the target cyclosporine C2 concentration, thus decreasing toxicity and improving graft function. We enrolled 80 kidney recipients in a single-center study comparing 2 cyclosporine-based protocols. Group I patients (n = 40) received a standard dose of cyclosporine (blood cyclosporine C2, 800-1500 ng/mL) with MMF and standard doses of corticosteroids. Group II patients (n = 40) were treated with a low dose of cyclosporine (blood cyclosporine C2, 450-800 ng/mL) and MMF plus low doses of corticosteroids after induction 48 hours before surgery with cyclosporine and MMF. Patient (97.5% vs 100%) and graft survivals (92.5% vs 95%) at 1 year were not different between the groups, although patients in group II experienced significantly fewer acute rejection episodes (10% vs 30%; P < .01). Delayed graft function occurred less often among group I than group II (17.5 vs 20%), but the difference was not significant. Graft function at 1 year was significantly better among group II (serum creatinine 1.31 vs 1.64 mg/dL and creatinine clearance 63 mL/min versus 47 mL/min; P < .05). We concluded that administration of cyclosporine and MMF 48 hours before renal transplantation allowed the safe effective use of low target C2 cyclosporine concentrations, enabling an early decrease in cyclosporine dose. These preliminary results indicated better 1-year graft function compared with the normal cyclosporine dose regimen.     

Long-term outcome of gastrointestinal complications in renal transplant patients treated with mycophenolate mofetil

This study examined consequences of gastrointestinal (GI) complications and mycophenolate mofetil (MMF) discontinuation on long-term outcomes in patients who received MMF at transplantation and had graft function 12 months post-transplantation. Data were obtained from the United States Renal Data System for cadaveric renal transplant recipients between 1995 and 1998. GI complications or MMF discontinuation occurred in 27.4% and 17.5% of patients, respectively. MMF was discontinued in 21.3% of patients with GI complications and 16.0% of patients without (P<0.00001). Four-year graft survival was reduced from 87.1% to 82.3% (P=0.091) with MMF discontinuation, to 83.0% (P=0.001) with GI complications, and to 70.2% (P<0.0001) with GI complications and MMF discontinuation. While the retrospective nature of this work cannot prove causality, which will require future prospective studies, both GI complications and MMF withdrawal are associated with increased risk of graft loss and may warrant further study in the management of transplant recipients.This work was performed while M.A. Schnitzler was at Washington University, St. Louis, Missouri, USA     

Elective withdrawal of mycophenolate mofetil in renal transplant recipients treated with mycophenolate mofetil, cyclosporine, and prednisone

In a retrospective study we investigated the risk of acute rejection after the withdrawal of mycophenolate mofetil (MMF) in 39 adult patients treated with cyclosporine (CyA), prednisone, and MMF for at least 6 months following renal transplantation. After reaching a stable renal graft function, MMF was withdrawn and CyA and prednisone were continued. Preceding the withdrawal of MMF, four patients experienced an acute rejection. During a median follow-up of 38 months after discontinuing MMF, no acute rejection occurred. The mean serum creatinine level did not change during the first 6 months after withdrawal of MMF. We conclude that elective withdrawal of MMF in stable renal transplant recipients at 6 months after transplantation bears no important risk of an occurrence of acute rejection. Received: 24 November 1999 Revised: 11 May 2000 Accepted: 18 December 2000     

Differential influence of azathioprine and mycophenolate mofetil on the disposition of basiliximab in renal transplant patients

Pharmacokinetic sampling was performed in two multicenter trials in which basiliximab (anti-CD25 monoclonal antibody) was administered with triple immunosuppression consisting of cyclosporine microemulsion, corticosteroids, and either azathioprine or mycophenolate mofetil. Blood samples were collected over 12 wk post-transplant from 31 azathioprine-treated and 66 mycophenolate mofetil-treated patients. Empirical Bayes estimates of each patient's basiliximab disposition parameters were derived and the duration of CD25 saturation was estimated as the time over which serum concentrations exceeded 0.2 microg/mL as confirmed by flow cytometry measurements. Basiliximab clearance was 29+/-14 mL/h when coadministered with azathioprine and 18+/-8 mL/h with mycophenolate mofetil. Both were significantly lower compared with a clearance of 37+/-15 mL/h from a previous study of basiliximab with dual therapy (p<0.001). As a consequence of the lower clearance of basiliximab, the durations of CD25 saturation were prolonged in the presence of azathioprine (50+/-20 d; range, 13--84) and mycophenolate mofetil (59+/-17 d; range, 28--94) compared with dual therapy (36+/-14 d; range, 12--91). A total of 27 acute rejection episodes occurred during the first 6 months in the two studies. Durations of CD25 saturation were not different in these patients compared with those who remained rejection-free in each study. A single patient among 57 who were screened developed anti-idiotype antibodies to basiliximab. The average duration of CD25 saturation was prolonged by 39 and 64% in the presence of azathioprine and mycophenolate mofetil, respectively. This graded effect was also observed for basiliximab clearance and may be due in part to a differentially reduced humoral response to basiliximab. Nonetheless, the range of CD25 saturation durations and basiliximab clearances did not extend outside the range when basiliximab was used with dual therapy in the absence of these agents. Hence, no dosing adjustment is deemed necessary when basiliximab is used in triple immunosuppressive therapy including either azathioprine or mycophenolate mofetil.     

Improvement of impaired renal function in heart transplant recipients treated with mycophenolate mofetil and low-dose cyclosporine

BACKGROUND: Cyclosporine (CsA) nephrotoxicity is a common problem after cardiac transplantation. We have studied the impact of CsA dose reduction in association with mycophenolate mofetil (MMF) treatment on renal function in heart transplant recipients with suspected CsA nephrotoxicity (serum creatinine level >2 mg/dl). METHODS: Twelve heart transplant recipients (11 men, 1 woman; 111 to 1813 days after transplantation) with CsA-based immunosuppression (plus azathioprine and/or steroids) and a serum creatinine level >2.0 mg/dl were started on a daily dose of 2000 mg of MMF. Dilated cardiomyopathy was the underlying disease in nine patients, ischemic cardiomyopathy in three patients. Mean patient age was 57 years (range 44-69 years). Azathioprine was discontinued and CsA slowly tapered. Creatinine clearance, serum creatinine level, urea nitrogen, and uric acid were monitored. CsA levels were measured, and CsA dose was adjusted for whole blood levels of 70-120 microg/L. Ten patients still had endomyocardial biopsies, whereas one had echocardiographic controls only. RESULTS: One grade 1B rejection episode according to ISHLT (International Society for Heart and Lung Transplantation) was observed until 1 year after the switch to MMF. One patient was excluded due to gastrointestinal side effects. CONCLUSIONS: Conversion from azathioprine to MMF with consecutive reduction of CsA in heart transplant recipients with CsA-impaired renal function improves renal function as evidenced by lower serum creatinine, urea nitrogen, uric acid, and higher creatinine clearance.     

Mycophenolic acid metabolite profile in renal transplant patients receiving enteric-coated mycophenolate sodium or mycophenolate mofetil

Mycophenolate mofetil (MMF), a prodrug of mycophenolic acid (MPA), is an effective immunosuppressive treatment in renal transplant recipients but is known to have gastrointestinal side effects. Enteric-coated mycophenolate sodium (EC-MPS; myfortic) is a new formulation for delivering MPA. This open-label, two-period, cross-over study was carried out to characterize the time course of MPA and its metabolites, mycophenolic acid glucuronide (MPAG) and acyl mycophenolic acid glucuronide (AcMPAG) in stable renal transplant patients (n = 40) after 28-day chronic dosing with EC-MPS (720 mg bid) or MMF (1000 mg bid). The relative abundance and exposure of all three compounds was also assessed. EC-MPS demonstrated the typical pharmacokinetic profile of an enteric-coated formulation with a delayed release of MPA compared with MMF (Tmax 2.5 versus 1.0 hours, respectively). Consistent with a similar disposition of MPA, both EC-MPS and MMF treatments resulted in the same ratio of MPAG to MPA exposure, 23:1. Furthermore, comparison of the AUC of MPAG and AcMPAG for both treatments indicated that steady state MPAG exposure was 75 to 90 times that of AcMPAG, confirming MPAG as the predominant metabolite of MPA. AcMPAG has been identified as a possible active metabolite of MPA; the present study indicates that AcMPAG may contribute around 14% of the exposure to active drug after administration of MPA. Both EC-MPS and MMF treatments were well tolerated over the 1-month period of chronic treatment. In summary, consistent with its enteric-coated design, EC-MPS delays delivery of MPA, but results in similar exposure to that provided by MMF.     

Posttransplant lymphoproliferative disorder among renal transplant patients in relation to the use of mycophenolate mofetil

BACKGROUND: The introduction of increasingly effective immunosuppressants has raised the question of whether posttransplant lymphoproliferative disorder (PTLD), a complication of immunosuppression, would become more frequent. This study assessed the risk of PTLD in relation to immunosuppression during a period that saw the introduction and eventual market dominance of mycophenolate mofetil (MMF). METHODS: A case-control study was conducted at 23 U.S. transplant centers. All participants received a renal-only transplant on or after July 1, 1995. PTLD cases were reported by centers and confirmed by central review. The United Network for Organ Sharing (UNOS) supplemented case ascertainment and identified controls matched on center, transplant date, and age. Center personnel abstracted risk factor and therapy data for cases and up to four controls per case. Cases and controls were compared, using a matched multivariate analysis, to assess the impact of MMF as one component of triple-therapy adjusted for other drug therapies and known risk factors. RESULTS: Data were collected for 108 PTLD cases and 404 controls. PTLD risk for individuals on triple therapy with MMF was similar to the risk experienced by individuals on triple therapy with no MMF (adjusted odds ratio=1.19; 95% CI 0.55-2.55). There was no dose response relationship between MMF and PTLD risk. CONCLUSIONS: Use of MMF was not associated with an increase in PTLD among patients who received triple immunosuppressive therapy, but an excess in risk as large as 155% or a reduction in risk by as much as 45% cannot be ruled out.     

Pharmacokinetics of mycophenolate mofetil in kidney transplant patients with renal insufficiency

Mycophenolate mofetil (MMF) is an immunosuppressant that is widely used for prophylaxis of rejection in solid organ transplantation. In this study, we examined the effect of renal insufficiency on the pharmacokinetics of MMF, particularly on the free fraction of drug in renal transplant patients. Our study was performed on 10 patients with severe renal insufficiency (creatinine clearance [CrCl] <30 mL/min), and 10 control patients with preserved renal function (CrCl >90 mL/min). All the patients had received a cadaveric donor graft at least 1 year prior and were clinically stable under treatment with MMF and cyclosporine. For each patient, we determined 12-hour areas under the curve (AUC(0-12 h)) for the metabolites: mycophenolic acid (MPA), 7-O-mycophenolic acid glucuronide (MPAG), and the free non-protein-bound fraction of MPA (f-MPA). The two groups were matched for age, sex, and MMF dose. Mean AUC(0-12 h) values for MPA were similar in both groups. The renal insufficiency group showed a significantly increased AUC(0-12 h) for MPAG (1550 +/- 392 vs 3527 +/- 1130 microg.h/mL, P < .001) and increased trough and AUC(0-12 h) values for f-MPA (0.023 +/- 0.02 vs 0.094 +/- 0.07 microg/mL, P = .003, and 0.87 +/- 0.3 vs 1.52 +/- 0.8 microg . h/mL, P = .016, respectively). We proposed that these differences should be taken into account when deciding upon the dose of this drug for the subset of patients with impaired transplant function.     

Improvement of renal function in pediatric heart transplant recipients treated with low-dose calcineurin inhibitor and mycophenolate mofetil

BACKGROUND: Renal dysfunction is a major complication in heart transplant recipients treated with calcineurin inhibitors. The goal of the study was to investigate the effect of a reduction of calcineurin inhibitor dosage with the concomitant introduction of mycophenolate mofetil on both renal function and cardiac allograft function. METHODS: Fourteen of 52 consecutive pediatric cardiac allograft recipients experienced a progressive decrease of renal function. A renal biopsy was performed before the dose of calcineurin inhibitors was reduced by 50% and azathioprine was replaced by mycophenolate mofetil. Renal function was evaluated by inulin clearance and maximal urinary osmolality before and yearly after the therapeutic changes. Acute rejection was monitored clinically, by echocardiography and endomyocardial biopsies. RESULTS: Inulin clearance in the fourteen children decreased from 84.2 mL/min/1.73 m at one year posttransplantation to 46.5+/-9.6 mL/min/1.73 m at the time of the change in immunosuppressive therapy. Significant renal lesions were observed in the renal biopsies performed before the change. At 1 year, inulin clearance had increased by 67%. In six patients who had a second determination 2 years after the switch, inulin clearance was not significantly different from the value at 1 year. There were three reversible acute rejection episodes in three patients. The incidence of rejection episodes was not different from a control group of patients whose treatment was not changed. CONCLUSION: The reduction of calcineurin inhibitor dosage and replacement of azathioprine by mycophenolate mofetil is a safe way to improve renal function in children with heart transplants and calcineurin inhibitor induced nephrotoxicity.     

Disseminated varicella infection in pediatric renal transplant recipients treated with mycophenolate mofetil.

BACKGROUND: Mycophenolate mofetil (MMF) is a new immune suppressive agent, effective in the prevention of acute rejection after renal transplantation. METHODS: The study was a retrospective review of records of pediatric renal transplant recipients from 1985 to the present. RESULTS: Since October 1995, the immune suppression protocol for pediatric renal transplant recipients at Mayo Eugenio Litta Children's Hospital has included MMF, prednisone, and cyclosporine A. During that time, 19 children and adolescents have received renal allografts, 17 of whom were seropositive for varicella antibody before transplantation, while 2 were seronegative. Varicella infection occurred in 3 of 19 patients (15.8%), all 3 of whom had serologically documented immunity to varicella virus before transplantation. All episodes occurred within 12 months of transplantation. All had generalized vesicular lesions without dermatomal distribution. None of the patients developed fever, respiratory, mucocutaneous, or central nervous system manifestations. All were managed with oral acyclovir, and had an uncomplicated recovery without neuralgia. By contrast, of 74 consecutive patients transplanted before use of MMF, only 1 patient (1.4%) had varicella infection after transplantation (P=0.026). CONCLUSION: The enhanced immunosuppression achieved with MMF appears to be associated with increased susceptibility to varicella infection.     

Intestinal microsporidiosis occurring in two renal transplant recipients treated with mycophenolate mofetil.

BACKGROUND: Intestinal microsporidiosis is a major cause of chronic diarrhea and malabsorption in patients with human immunodeficiency virus. Its occurrence in transplant recipients has exceptionally been reported to date. METHODS: We report what we believe are the first two cases of intestinal microsporidiosis in renal transplant recipients. The patients were treated with mycophenolate mofetil. RESULTS: The clinical presentation was chronic diarrhea with massive weight loss. Stool analysis revealed microsporidian spores, identified as Enterocytozoon bieneusi spores by polymerase chain reaction. The onset of this opportunistic infection in these two patients is believed to be secondary to an increase in immunosuppression after azathioprine replacement by mycophenolate mofetil. The withdrawal of mycophenolate mofetil led to clinical recovery. CONCLUSION: The incidence of microsporidiosis will probably increase in transplant recipients treated with powerful immunosuppressants. Therefore, we recommend a systematic search for microsporidian spores in stool specimens in cases of unexplained diarrhea in these patients.