RS-61443 (mycophenolate mofetil). A multicenter study for refractory kidney transplant rejection

A Limited Sampling Strategy for Therapeutic Drug Monitoring of Mycophenolate Mofetil for Prophylaxis of Acute Graft-Versus-Host Disease in Allogeneic Stem Cell Transplantation

A universally accepted strategy for therapeutic drug monitoring (TDM) of mycophenolate mofetil (MMF) in the prevention of acute graft-versus-host disease (aGVHD) in allogenic hematopoietic stem cell transplantation (alloHSCT) does not exist. We explored the feasibility of developing a limited sampling strategy (LSS) for TDM of MMF in this setting. Patients undergoing alloHSCT received standard MMF-cyclosporine prophylaxis, with MMF administered twice daily (BD) for matched transplant recipients or thrice daily (TID) in haploidentical transplantation. Intensive blood sampling was carried out on day 7 and area under the concentration–time curve (AUC) of mycophenolic acid (MPA), the active metabolite, was estimated using noncompartmental analysis. The ability of MPA exposure defined by AUC_0-12 to discriminate between responders (patients who did not develop GVHD) and nonresponders (patients who developed GVHD) was determined by receiver operating characteristic curve analysis. Patients were divided into training and validation sets within BD and TID groups. Mathematical equations were developed from the training set to predict AUC_0-12 from an abbreviated AUC involving a limited number of sampling points. The equations were validated in the validation set by comparing the MPA AUC_0-12 predicted from LSS with the observed AUC_0-12. It was observed that patients with AUC_0-12 ≤18.99 mg*h/L had a higher risk of developing aGVHD [odds ratio (OR) = 2.63 (1.17 to 5.87), P = 0.06]. The benefit was more in matched transplant recipients [OR = 3.5 (1.30 to 9.49), P = 0.05] as compared to haploindentical transplant [OR = 2.8 (0.49 to 15.91), P = NS]. Using the mathematical equations, the observed AUC_0-12 was predicted with 92.31% accuracy in the BD subset and 100% accuracy in the TID subset for a combined accuracy of 94.76%. A set of just three samples that constituted the abbreviated AUC_1-4 was used to develop the predictive models. The LSS could be employed for the therapeutic monitoring of MMF particularly in patients undergoing matched hematopoietic stem cell transplantation.

Real-World Experience of Safety of Mycophenolate Mofetil in 119 Japanese Patients with Systemic Lupus Erythematosus: A Retrospective Single-Center Study

Objectives

Mycophenolate mofetil (MMF) is the standard treatment for lupus nephritis. In Japan, it was approved for lupus nephritis in 2015. We investigated its real-world safety and effectiveness in Japanese patients with systemic lupus erythematosus (SLE).

Methods

We analyzed the continuation rate, adverse events, and reasons for discontinuation of MMF in Japanese patients with SLE in a retrospective single-center study. We included 119 patients who received MMF from 31 July 2015 to 31 May 2019. To compare demographic and clinical characteristics between groups, the Mann–Whitney U-test was used for nonnormally distributed variables. Categorical variables were compared using Fisher's exact test. Kaplan–Meier curves were plotted for the discontinuation rate of MMF.

Results

Patients consisted of 18 males and 101 females. Thirty-five patients discontinued MMF. The cumulative discontinuation rate was 42.4%. Twenty-nine patients discontinued MMF due to adverse events, and six patients discontinued MMF due to remission of SLE or desire for childbearing. At the time of the last observation, the lupus low disease activity state achievement rate was significantly lower in patients who experienced adverse events than those who did not (64% vs. 35%, P = 0.009). We examined the concentration of mycophenolate acid (trough level) in stored frozen serum in 11 patients. Two patients had irreversible complications due to viral meningitis; their trough mycophenolate acid concentrations were 8.3 and 6.3 μg/mL, respectively.

Conclusions

Although MMF may be effective in Japanese patients with SLE, physicians should pay attention to infections in patients with high mycophenolate acid concentrations.

Targeting Calcium Release-activated Calcium Channel Is Not Sufficient to Prevent Rejection in Nonhuman Primate Kidney Transplantation

BACKGROUND

Calcineurin inhibitors successfully control rejection of transplanted organs but also cause nephrotoxicity. This study, using a rhesus monkey renal transplantation model, sought to determine the applicability of a new immunomodulatory drug inhibiting the store-operated calcium release-activated calcium channel of lymphocytes to control transplant rejection without nephrotoxicity.

METHODS

Animals underwent kidney transplantation and were treated with tacrolimus alone (n = 3), a CRACM1 inhibitor (PRCL-02) (n = 6) alone, or with initial tacrolimus monotherapy followed by gradual conversion at 3 weeks to PRCL-02 alone (n = 3). PRCL-02 was administered via a surgically inserted gastrostomy tube BID.

RESULTS

Dose-related drug exposure in monkeys was established and renal transplants were then performed using PRCL-02 monotherapy. Oral dosing of PRCL-02 was well tolerated and resulted in suppressed T-cell proliferation in in vitro MLR comparable to animals in the tacrolimus control arm. Animals receiving tacrolimus monotherapy were e on day 100 without rejection. PRCL-02 monotherapy only marginally prolonged graft survival (MST = 13.16 d; group 2) compared with untreated controls. Animals treated initially with tacrolimus and converted to PRCL-02 monotherapy had a mean graft survival of 35.3 days which was prolonged compared with PRCL-02 monotherapy but not compared with the tacrolimus-treated group. Pharmacokinetic studies showed inconsistent drug exposures despite attempts to adjust dose and exposure which may have contributed to the rejections.

CONCLUSIONS

We conclude that, in this nonhuman primate model of kidney transplantation, PRCL-02 demonstrated evidence of in vivo immunosuppressive activity but was inferior to tacrolimus treatment with respect to suppressing immune transplant rejection.

Mycophenolate and nephrology

Several large, randomized trials have established mycophenolate mofetil (MMF) as an effective immunosuppressant for kidney transplantation. Inhibition of inosine 5′-monophospate dehydrogenase (IMPDH) by MMF appears to have pleiotropic effects on both immune and non-immune cells. In addition to B- and T-cell inhibition, in vitro and in vivo data suggest that MMF also has inhibitory effects on smooth muscle cells, endothelial cells, and myofibroblasts, findings that may be relevant in considering treatment of primary immune mediated kidney diseases. Clinical trials have established the efficacy of MMF for the treatment of lupus nephritis, as discussed in detail elsewhere in this supplement. Although animal studies have provided the rationale for human trials of MMF in primary glomerular diseases, most of the evidence thus far is conflicting or based largely on pilot studies. Data from larger, controlled trials will soon emerge and may clarify the role of MMF in the treatment of these disorders.

Advances in pharmacotherapy to treat kidney transplant rejection

INTRODUCTION

Current immunosuppressive combination therapy provides excellent prevention of T-cell-mediated rejection following renal transplantation; however, antibody-mediated rejection remains of high concern and accounts for a large number of long-term allograft losses. The recent development of protocol biopsies resulted in the definition of subclinical rejection (SCR), showing histologic evidence for rejection but unremarkable clinical course.

AREAS COVERED

This review describes the current knowledge and evidence of pharmacotherapy to treat kidney allograft rejections and covers SCR treatment options. Each substance is analyzed with regard to its classical indication and further discussed for the treatment of other forms of rejection.

EXPERT OPINION

Despite a lack of randomized trials, early acute T-cell-mediated rejection can be treated effectively in most cases without graft loss. The necessity to treat SCR is currently unclear. Due to a lack of effective therapies, new treatment approaches for antibody-mediated rejection are an urgent medical need to improve long-term outcomes. Future research should aim to better define pathophysiology and histology, stratify risk, and develop rational treatment strategies from randomized controlled trials, in order to establish the value of novel therapies in the arsenal of rejection pharmacotherapy. However, the effective prevention of rejection with minimal side effects still remains the goal in immunosuppression.

Reassessing the Significance of Intimal Arteritis in Kidney Transplant Biopsy Specimens

Intimal arteritis (the presence of v-lesions) in kidney transplant biopsy specimens is believed to have major prognostic and diagnostic significance. We assessed the relationship of v-lesions to prognosis in 703 indication biopsy specimens and used microarray-based molecular tests to re-examine the relationship of v-lesions to rejection. v-Lesions were noted in 49 specimens (7%) and were usually mild (v1). The presence of v-lesions had no effect on graft survival compared with the absence of v-lesions. Pathologists using current conventions almost always interpreted v-lesions as reflecting T cell-mediated rejection (TCMR), either pure or mixed with antibody-mediated rejection (ABMR). The molecular scores questioned the conventional diagnoses in 29 of 49 specimens (59%), including ten that were conventional TCMR with no molecular rejection and nine that were conventional TCMR mixed with pure ABMR molecularly. The presence of tubulointerstitial inflammation (i-t) meeting TCMR criteria allowed subclassification of v-lesion specimens into 21 i-t-v-lesion specimens and 28 isolated v-lesion specimens. Molecular TCMR scores were positive in 95% of i-t-v-lesion specimens but only 21% of isolated v-lesion specimens. Molecular ABMR scores were often positive in isolated v-lesion biopsies (46%). Time of biopsy after transplantation was critical for understanding isolated v-lesions: most early isolated v-lesion specimens had no molecular rejection and were DSA negative, whereas most isolated >1 year after transplantation had positive DSA and ABMR scores. Therefore, v-lesions in indication biopsy specimens do not affect prognosis and can reflect TCMR, ABMR, or no rejection. Time after transplantation, DSA, and accompanying inflammation provide probabilistic basis for interpreting v-lesions.

Improvement of renal graft function after conversion from a calcineurin inhibitor including immunosuppression to a mycophenolate sodium including regimen: a 4-year follow-up

BACKGROUND

The most common immunosuppressive regimens after renal transplantation include calcineurin inhibitors (CNI). However, due to renal toxicity long-term graft survival does not seem to be positively affected by CNIs.

METHODS

In the present study, we investigated 17 patients, in which the CNI immunosuppression was converted to a CNI-free, mycophenolate sodium (MPS) regimen. Conversion was performed due to progressive impairment of the graft function from suspected CNI toxicity. We retrospectively analyzed graft function as well as toxicity and surrogate markers for 4 years before and 4 years after conversion using a repeated-measures mixed model data analysis and/or a paired sample t-test.

RESULTS

The mean time point of therapy conversion was 11.2 ± 4.6 years after transplantation. Within 1 month of CNI discontinuation, allograft function improved significantly, remaining at a significant level for 2 years. The estimated glomerular filtration rate increased from 43.4 ± 14.8 to a maximum of 55.7 ± 21.7 mL/min at 1 year after conversion (P = .0027). After 4 years, the end of the observation period, renal function was similar to the baseline. There were no significant side effects.

CONCLUSION

These data suggested that, when chronic CNI-toxicity is suspected, renal allograft recipients may benefit from CNI withdrawal in favor of a MPS-including immunosuppressive regimen.

Lung transplant infection

Lung transplantation has become an accepted therapeutic procedure for the treatment of end‐stage pulmonary parenchymal and vascular disease. Despite improved survival rates over the decades, lung transplant recipients have lower survival rates than other solid organ transplant recipients. The morbidity and mortality following lung transplantation is largely due to infection‐ and rejection‐related complications. This article will review the common infections that develop in the lung transplant recipient, including the general risk factors for infection in this population, and the most frequent bacterial, viral, fungal and other less frequent opportunistic infections. The epidemiology, diagnosis, prophylaxis, treatment and outcomes for the different microbial pathogens will be reviewed. The effects of infection on lung transplant rejection will also be discussed.

Monitoring of nonsteroidal immunosuppressive drugs in patients with lung disease and lung transplant recipients: American College of Chest Physicians evidence-based clinical practice guidelines

OBJECTIVES

Immunosuppressive pharmacologic agents prescribed to patients with diffuse interstitial and inflammatory lung disease and lung transplant recipients are associated with potential risks for adverse reactions. Strategies for minimizing such risks include administering these drugs according to established, safe protocols; monitoring to detect manifestations of toxicity; and patient education. Hence, an evidence-based guideline for physicians can improve safety and optimize the likelihood of a successful outcome. To maximize the likelihood that these agents will be used safely, the American College of Chest Physicians established a committee to examine the clinical evidence for the administration and monitoring of immunosuppressive drugs (with the exception of corticosteroids) to identify associated toxicities associated with each drug and appropriate protocols for monitoring these agents.

METHODS

Committee members developed and refined a series of questions about toxicities of immunosuppressives and current approaches to administration and monitoring. A systematic review was carried out by the American College of Chest Physicians. Committee members were supplied with this information and created this evidence-based guideline.

CONCLUSIONS

It is hoped that these guidelines will improve patient safety when immunosuppressive drugs are given to lung transplant recipients and to patients with diffuse interstitial lung disease.

Mycophenolate mofetil in children with steroid/cyclophosphamide-resistant nephrotic syndrome

The purpose of this study was to assess the results of therapy with mycophenolate mofetil (MMF) in children with idiopathic nephrotic syndrome (INS) who were both steroid- and cyclophosphamide-resistant. Treatment lasted a minimum of 6 months, and follow-up data were collected over a 2-year period. The children were divided into two groups: Group 1 (n=34) comprised patients who had received cyclosporine A (CsA) before the initiation of MMF therapy; Group 2 (n=18) comprised patients who received only MMF. Among the 34 patients of Group 1, complete and partial remission were achieved in seven (20.6%) and 13 patients (38.6%), respectively; there was no response in 14 patients (41.2%). Among the 18 patients in Group 2, complete and partial remission occurred in five (27.8%) and six (33.3%) patients, respectively; there was no response in seven patients (38.9%). Eight patients developed chronic kidney disease. The main side-effects were gastrointestinal complaints (n=11, 21%), recurring severe infections (n=1, 1.9%), and mild thrombocytopenia/leucopenia (n=1, 1.9%). MMF proved to be therapeutically effective in 59.5% of the cases. These beneficial effects need to be confirmed in studies with a long-term follow-up after discontinuation of the treatment. Our statistical analysis of the results of therapy with MMF did not reveal any significant difference between its use alone or following CsA administration.

Mycophenolate in dermatology

Originally used to treat psoriasis nearly three decades ago, mycophenolic acid, reformulated as mycophenolate mofetil (MMF), has been rediscovered by the world of dermatology. As a relatively well-tolerated immunosuppressive used in organ transplant recipients, MMF has recently been reported to show promise for several dermatologic conditions, including psoriasis, pemphigus vulgaris, pyoderma gangrenosum, bullous lichen planus, and even connective tissue diseases such as lupus erythematosus and dermatomyositis. Although not intended to be exhaustive, this review discusses MMF with regard to its basic pharmacology, its side effects, and its reported efficacy in a variety of dermatologic indications. Relevant literature was retrieved by a Medline search combining the terms "mycophenolate" or "mycophenolic acid" and "skin" or "skin disease" or a number of specific conditions ("psoriasis", "dermatitis", "eczema", "pemphigoid", "pemphigus", "vasculitis", "pyoderma gangrenosum", "Crohn's disease", "graft-versus-host disease", "lichen planus"). As MMF has only been recently re-introduced for dermatologic application, the nature of much of the literature is admittedly that of case reports or case series. Nevertheless, the results are sufficiently promising to warrant further larger, control studies.

Uncommon Side Effect of MMF in Renal Transplant Recipients

Mycophenolate mofetil (MMF) is a potent immunosuppressive agent used in renal transplantation. Gastrointestinal and hematological side effects are commonly observed, but hepatotoxicity has not been reported. In this study, we assessed MMF-related hepatotoxicity in renal transplant recipients. A total of 124 renal transplantation recipients (RTRs) were evaluated for elevated liver enzymes associated with MMF, and 79 patients were enrolled to the study. Patients used MMF 2 g/day. The patients who had progressive increase in liver enzymes after renal transplantation and their AST, ALT, GGT, ALP, bilirubin levels, hepatitis, cytomegalovirus (CMV), abdominal ultrasonography, duration of hepatotoxicity, and decreased dosage or withdrawal of MMF were recorded. Also, we evaluated their liver enzymes while the patients were on the waiting list. Of the 79 patients, 11 patients (13.9%) had a progressive increase in liver enzymes. The median (min-max) age of the patients with MMF-hepatotoxicity was 29 (19-54) and 72.7% of them were male. None of the patients had hepatitis B or C, CMV infection, or other possible causes for elevated liver enzymes and their abdominal ultrasonography were normal. High liver enzyme levels regressed after the withdrawal (n=6) or reduce dosage (n=5) of MMF. The median time of the increase in liver enzymes was 28 (4-70) days and after 50% reduction or withdrawal of MMF, returned to normal values in 16 (4-210) days. The median levels of ALT in waiting list (I), before (II), and after (III) reduction dosage or withdrawal of MMF were 22.0 (3-22), 222.0 (51-508), and 33.0 (21-64) U/L, respectively (p I-II=0.004,p I-II=0.013, andp II-III=0.005). There were no differences for ALP, GGT, total bilirubin, and direct bilirubin levels. Also, the correlation between recovery time of ALT and persistence time of ALT elevation before adjustment of MMF was significant (r=0.739, p=0.009). Consequently, after renal transplantation, hepatotoxicity can occur due to a lot of reason including MMF usage. If hepatotoxicity related to MMF is not considered, especially in the early period of renal transplantation, resolution of hepatotoxicity can be required long term.

Gender-Related Differences in Mycophenolate Mofetil-Induced Gastrointestinal Toxicity in Rats

Mycophenolate mofetil (MMF), the prodrug of mycophenolic acid (MPA), is included in current combination immunosuppressive regimens following organ transplant. Treatment with MMF often results in dose-limiting gastrointestinal (GI) side effects. The underlying mechanisms responsible for these side effects are not fully understood, but exposure of the intestinal epithelia to MPA during enterohepatic recycling may be involved. The present study demonstrated that female rats are more susceptible to MMF-induced GI toxicity than male rats. Female Sprague-Dawley rats treated chronically with an oral dose of 50 mg of MPA equivalents/kg/day experienced greater GI toxicity than male rats, as measured by diarrhea grade and weight loss. Intestinal microsomes harvested from the upper jejunum of female rats had approximately 3-fold lower MPA glucuronidation rates compared with male rats. In the remaining areas of the small and large intestine, there was also a trend toward decreased glucuronidation in the female rats. The area under the plasma concentration-time curve (AUC) for MPA following an oral dose of 50 mg of MPA equivalents/kg was roughly similar between genders, whereas the AUC for mycophenolic acid phenolic glucuronide (MPAG) was significantly lower in female rats. Female rats also excreted half of the biliary MPAG as male rats. The greater susceptibility of female rats to MMF-induced gastrointestinal toxicity, despite diminished intestinal MPA exposure via reduced biliary excretion of MPAG, may result from reduced protection of enterocytes by in situ glucuronidation. Likewise, susceptibility to MMF-induced GI toxicity in humans may also result from variable intestinal glucuronidation due to UDP glucuronosyltransferase polymorphisms or differential expression.

Clinical pharmacokinetics of mycophenolate mofetil in Japanese renal transplant recipients: A retrospective cohort study in a single center

Mycophenolate mofetil (MMF), a morpholinoethyl ester of mycophenolic acid (MPA), is currently widely used in organ transplantation as an immunosuppressant. The usefulness of therapeutic drug monitoring (TDM) of MPA after MMF dosing is not clear in Japanese renal transplant patients. In this study, to obtain more information for TDM of MPA, the association between MPA pharmacokinetic characteristics and the development of the side effects, and the effect of other concomitant immunosupressants such as cyclospoline A (CyA), tacrolimus (FK) and predonisolone (PSL) on MPA pharmacokinetics were investigated in detail. Moreover, the effects of enterohepatic recirculation (EHRA) on pharmacokinetic characteristics of MPA and the development of the side effects were also investigated. AUC(MPA)(0-9) with FK medication was 1.3-1.9 times higher than that with CyA medication, and the contribution to the plasma level of MPA of FK might be smaller than that of CyA, because EHRA inhibition by CyA was 2 times greater than that by FK. AUC(MPA)(0-9) was not influenced by PSL. The association between AUC(MPA)(0-9) and the development of the side effects was not observed; however, the development of side effects (leukopenia and diarrhea) in the EHRA group was 2 times higher than that in the non-EHRA group. These results suggested that TDM for MPA after MMF dosing was desirable in Japanease transplant patients. However, though not frequently, AUC obtained by multiple blood sampling after MMF dosing was needed. In addition, EHRA has led to increasing interest in MMF medication.

De novo GMP synthesis is required for axon guidance in Drosophila

Guanine nucleotides are key players in mediating growth-cone signaling during neural development. The supply of cellular guanine nucleotides in animals can be achieved via the de novo synthesis and salvage pathways. The de novo synthesis of guanine nucleotides is required for lymphocyte proliferation in animals. Whether the de novo synthesis pathway is essential for any other cellular processes, however, remains unknown. In a search for genes required for the establishment of neuronal connectivity in the fly visual system, we identify the burgundy (bur) gene as an essential player in photoreceptor axon guidance. The bur gene encodes the only GMP synthetase in Drosophila that catalyzes the final reaction of de novo GMP synthesis. Loss of bur causes severe defects in axonal fasciculation, retinotopy, and growth-cone morphology, but does not affect photoreceptor differentiation or retinal patterning. Similar defects were observed when the raspberry (ras) gene, encoding for inosine monophosphate dehydrogenase catalyzing the IMP-to-XMP conversion in GMP de novo synthesis, was mutated. Our study thus provides the first in vivo evidence to support an essential and specific role for de novo synthesis of guanine nucleotides in axon guidance.

Review of Major Clinical Trials with Mycophenolate Mofetil in Renal Transplantation

Mycophenolate mofetil (MMF) was approved for the prevention of acute rejection following renal transplantation based on the results of three groundbreaking, large, clinical trials that demonstrated a significantly reduced risk of acute rejection in patients receiving MMF when compared with those receiving placebo or azathioprine. These three multicenter, prospective, double-blind trials performed at 55 transplant centers on three continents were the largest immunosuppressive drug trials ever attempted and the first prospective, randomized, double-blind trials ever performed in transplantation. These pivotal trials established a foundation for widespread acceptance of MMF in combination with cyclosporine and steroids as a maintenance regimen for renal transplant patients. The findings of these initial trials that led to the approval of MMF for renal transplantation, including long-term follow-up data, will be reviewed in this paper. The expanding scope of major trials of MMF, including trials in pediatric patients, combination regimens with novel induction therapies or other maintenance agents, and trials in special patient populations such as those at high immunological risk or with deteriorating kidney function, will also be discussed.

Intraindividual and interindividual variations in the pharmacokinetics of mycophenolic acid in liver transplant patients

The authors evaluated the intraindividual and interindividual variations in the pharmacokinetics of mycophenolic acid after oral administration of mycophenolate mofetil in 10 liver transplant patients. Mycophenolic acid and its metabolite, mycophenolic acid glucuronide, were measured in plasma and urine by high-pressure liquid chromatography. The plasma protein binding of mycophenolic acid was determined by ultrafiltration. The maximum concentration of mycophenolic acid in plasma increased significantly (P < or = .05) with time from 9.1 +/- 7.2 microg/mL (<1 week) to 36.7 +/- 15.6 microg/mL (1 month). The area under the plasma concentration versus time curve of mycophenolic acid also increased significantly with time, from 50.8 +/- 42.1 microg x h/mL to 118.0 +/- 57.6 microg x h/mL (P < or = .05). The plasma protein binding of mycophenolic acid increased from 92% to 98%, and the apparent oral clearance [CL/F] decreased from 32.9 +/- 21.4 L/h during the first study period to 9.0 +/- 4.4 L/h (P < or = .05) during the third study period. The apparent intrinsic clearance of mycophenolic acid did not change significantly over time. The ratio of the area under the curve of mycophenolic acid glucluronide to mycophenolic acid in plasma decreased with time (25.5 +/- 21.2 vs 8.0 +/- 3.3) but did not reach statistical significance. The increased binding of mycophenolic acid to plasma proteins with time after transplantation appeared to contribute to the intraindividual variation, whereas differences in the ability of the liver to metabolize mycophenolic acid between patients appear to contribute to the large interindividual variation in the pharmacokinetics of mycophenolic acid. The observations in this study support the concept of measuring the unbound concentration of mycophenolic acid to optimize immunosuppressive drug therapy with mycophenolic acid.

Mycophenolic mofetil reduces the HLA antibody response of children to valved allograft implantation

BACKGROUND

Valved allografts induce a brisk, broadly reactive human leukocyte antigen (HLA) antibody response in children after implantation. Mycophenolic mofetil (MMF) is a powerful immunosuppressant that inhibits the proliferation of both T cells and B cells and has been reported to possibly reduce HLA panel reactive antibody (PRA) in sensitized transplant recipients.

METHODS

The purpose of this study was to determine whether MMF can blunt the HLA antibody response to valved allografts in children. Eight patients completed (of 28 approached) a pilot study to determine the effects of 3 months of twice daily MMF (600 mg/m(2)/dose) on the HLA antibody response measured before surgery, at 1 month, and at 3 months after implantation. Patients were 7.5 +/- 4 yrs old (mean +/- standard deviation [SD]), with 5 patients undergoing repair of tetralogy of Fallot, 2 Ross procedures, and 1 aortic valve replacement.

RESULTS

In contrast to historical controls with a virtual 100% HLA class I PRA response to valved allograft implantation, MMF markedly decreased the HLA class I antibody response at 1 and 3 months postimplantation. In 6 cases where the HLA type of the donor was defined, PRA specificity correlated with incompatible antigens on the allograft. One patient withdrew after 2 weeks due to a sinus infection that was successfully treated with oral antibiotics, and 3 patients had a transient adverse effect of postoperative vomiting.

CONCLUSIONS

This study demonstrates the ability to pharmacologically abrogate the HLA class I antibody response to valved allograft implantation in children using MMF.

Mycophenolate mofetil inhibits differentiation, maturation and allostimulatory function of human monocyte-derived dendritic cells

We have studied the effect of mycophenolate mofetil (MMF), a new drug used in prevention of transplant rejection, on differentiation, maturation and allostimulatory activity of human monocyte-derived dendritic cells (MDDC). MDDC were generated in vitro with granulocyte macrophage-colony stimulating factor (GM-CSF) and interleukin (IL)-4 in the presence or absence of MMF. MMF reduced the number of immature MDDC in culture, dose-dependently, by inducing apoptosis and inhibited their stimulatory activity on allogeneic lymphocytes. These changes correlated with down-regulation of co-stimulatory and adhesion molecules such as CD40, CD54, CD80 and CD86. No differences were observed in mannose receptor (MR)-mediated endocytosis, measured by the uptake of fluorescein isothiocyanate (FITC)-dextran. MDDC differentiated in the presence of MMF showed significantly reduced maturation upon stimulation with lipopolysaccharide, as judged by lower expresson of CD83 and co-stimulatory molecules, lower production of tumour necrosis factor (TNF)-alpha, IL-10, IL-12 and IL-18 as well as lower stimulation of alloreactive T cells including naive CD4+ CD45RA+ T cells. In contrast, MDDC matured in the presence of MMF showed a more marked decrease in the FITC-dextran uptake than mature MDDC cultivated without MMF and the phenomenon correlated with down-regulation of the MR expression. These results suggest that MMF impairs differentiation, maturation and function of human MDDC in vitro, which is an additional mechanism of its immunosuppressive effect.

Daclizumab induction, tacrolimus, mycophenolate mofetil and steroids as an immunosuppression regimen for primary kidney transplant recipients

BACKGROUND

Recent reports have demonstrated the efficacy of interleukin-2-receptor blockers in lowering the incidence of early acute rejection in cyclosporine-treated kidney recipients when compared to patients not induced with an antibody product. The addition of daclizumab to a tacrolimus-mycophenolate mofetil-based immunosuppressive protocol was tested to evaluate whether there might be an additional reduction of the risk of rejection after renal transplantation.

METHODS

Since March 1998, we studied the effect of daclizumab in a nonrandomized, prospective study of 233 sequential recipients of first renal transplant. They were retrospective compared with a control group of 225 renal transplant recipients receiving a 10-day course of OKT3 induction, and tacrolimus, mycophenolate mofetil, and methylprednisolone maintenance. The study group received the same immunosuppressive regimen with the addition of daclizumab at 1 mg/kg for five doses over 10 weeks in the place of OKT3 therapy. There was at least 1HLA DR antigen compatibility match present between all donors and recipients. Patients were followed for 1 year after renal transplantation for the incidence of biopsy-proven acute rejection, patient and graft survival, and adverse events.

RESULTS

At 12 months, patient and graft survival for the daclizumab was 98 and 96 vs. 96 and 94% for the OKT3 group, respectively, and were not statistically different. Acute rejection rates (<6 months) were lower in the daclizumab group as compared with the OKT3 group, i.e., 5 (2.1%) vs. 16 (7.1%) (P=0.011) respectively. The incidence of infection requiring hospitalization appeared to be lower with daclizumab (7.3 vs. 16%, P<0.0036) with a similar trend with cyclomegalovirus infection, i.e., 1.6 vs. 4%, respectively (P=0.14).

CONCLUSIONS

The combination of daclizumab, tacrolimus, mycophenolate mofetil, and steroids is safe and effective for kidney transplant recipients in lowering the incidence of early acute rejection and without any increase in morbidity when compared to our previous protocol, which may have an eventual impact in long-term graft survival.

Adverse gastrointestinal effects of mycophenolate mofetil: aetiology, incidence and management

Mycophenolate mofetil (MMF) is a relatively new immunosuppressive drug. It inhibits inosine monophosphate dehydrogenase, a key enzyme in the de novo pathway of purine synthesis, and thus causes lymphocyte-selective immunosuppression. Large clinical trials have revealed the efficacy of MMF in the prevention of allograft rejection when administered together with cyclosporin or tacrolimus and corticosteroids. Although the adverse effect profile of MMF is comparatively benign, gastrointestinal adverse effects are a major concern. These effects are partially explained by the increased immune suppression, by the mode of action and by interactions, particularly with other immunosuppressants. The aetiology of the rarest gastrointestinal adverse effects is still not completely clear. Therapy depends upon the clinical gravity of the adverse effects and is therefore a case of waiting and ob- serving. An adjustment of dosage of immunosuppressants according to the clinical situation and, particularly in the case of MMF, spreading the total dosage over more than 2 daily doses are often sufficient. Should adverse effects persist for a longer period of time and be of a more serious nature, a comprehensive invasive diagnostic process is necessary, including endoscopy and biopsy and the search for opportunistic infections. In this case, dosage reduction or the complete withdrawal of MMF seems to be unavoidable. Severe gastrointestinal complications with MMF are rare, but when they do occur they may require extensive diagnosis and treatment. In the future, therapeutic drug monitoring and, where necessary, pharmacological modifications of MMF could lead to a further reduction of adverse effects with an equal or even increased efficacy.

Mycophenolate mofetil versus azathioprine in patients surviving the initial cardiac transplant hospitalization: an analysis of the Joint UNOS/ISHLT Thoracic Registry

BACKGROUND

Although the randomized mycophenolate mofetil- (MMF) azathioprine (AZA) trial is likely applicable to cardiac transplantation in general, it was limited to select and usually larger cardiac transplant centers and suffered from substantial cross-over and failure of many patients to receive assigned treatment drug.

METHODS

The Joint ISHLT/UNOS Thoracic Registry was analyzed for the effects of MMF versus AZA in patients 1) on a cyclosporine- (CsA) based immunosuppression protocol; 2) having survived long enough to be discharged from the transplant hospitalization.

RESULTS

A total of 5599 patients (4942 CsA/AZA and 657 CsA/MMF) were included with no significant differences between the MMF and AZA groups in baseline characteristics with the exception of recipient age (50 vs. 47 years), donor age (29 vs. 28 years), ischemic time (3.0 vs. 2.9 hr), and pretransplant medical condition (more AZA patients in ICU, more MMF patients on VAD). Actuarial survival was greater in the MMF group compared to the AZA group in patients surviving the initial transplant hospitalization (1 year 96 vs. 93%, 3 years 91 vs. 86%, P=0.0012). This difference was confirmed in the logistic regression analysis of 3-year mortality showing a relative risk of 0.62 (P=0.011).

CONCLUSIONS

These data provide independent support for the broad applicability of the positive results from the randomized MMF-AZA clinical trial in a substantially larger patient population and confirm improved survival in patients using mycophenolate mofetil compared to azathioprine late after cardiac transplantation.

Mycophenolate mofetil: suggested guidelines for use in kidney transplantation

Mycophenolate mofetil (MMF) is an immunosuppressive drug designed to inhibit inosine monophosphate dehydrogenase (IMPDH). IMPDH is a key enzyme in the de novo purine synthesis of lymphocytes. It is crucially important for proliferative responses of human T and B lymphocytes. The inhibition of IMPDH thus leads to selective lymphocyte suppression. After successful use in various in vitro and animal models, MMF was brought to clinical trial in patients undergoing transplantation. The drug is rapidly and completely absorbed following oral administration. Pilot studies of administration with cyclosporin and corticosteroids suggested a significant reduction in the incidence of organ rejection at dosages of 1 to 3 g/day. As a result of these studies, 3 pivotal randomised double-blind multicentre trials, involving nearly 1500 patients, were designed to investigate the effects of addition of MMF to different standard immunosuppressive protocols on the prevention of acute renal allograft rejection. After 6 months, the rates of biopsy-proven rejection were significantly reduced in patients receiving MMF. In combination with cyclosporin and corticosteroids, the adverse effect profile resembled that of azathioprine. Most adverse effects were associated with the gastrointestinal tract, the blood system and opportunistic infections. MMF offers improved immunosuppressive therapy following renal and probably other solid organ transplantation. MMF has been licensed since 1995 for the prevention of acute renal allograft rejection in most countries. It has been used in different combinations of immunosuppressive drugs and in various dosages and regimens.

Significant post-transplant hypogammaglobulinemia in six heart transplant recipients: an emerging clinical phenomenon?

BACKGROUND

The recent development of powerful agents such as mycophenolate mofetil and tacrolimus has altered current regimens for the prevention and treatment of allograft rejection. Questions have been raised about these newer regimens in terms of susceptibility to opportunistic infections and effects on host defenses. Severe hypogammaglobulinemia has been infrequently described in solid organ transplant recipients, but has been recently noted in six heart transplant recipients at one center, of whom five were receiving a combination of tacrolimus, mycophenolate mofetil, and prednisone.

METHODS

Case summaries of six recent heart transplant recipients with total immunoglobulin G (IgG) levels of less than 310 mg/dl, five of whom had cytomegalovirus (CMV) infection and three of whom had multiple infections including Nocardia, invasive Trichophyton, and Acinetobacter bacteremia. Previous literature was reviewed with the aid of a Medline search using the search terms hypogammaglobulinemia; kidney, liver, heart, lung, and organ transplantation; mycophenolate mofetil; tacrolimus; cyclosporine; azathioprine; and nocardiosis.

RESULTS

We here report six cardiac transplant recipients seen over a period of one year who were found to have immunoglobulin G levels of 310 mg/dl or below (normal: 717-1400 mg/dl). The first five patients were diagnosed because of evaluation for infections; the sixth, who was asymptomatic with an IgG level of 175, was found during screening for hypogammaglobulinemia instituted as a result of these first five patients. All six patients had received steroid pulses for rejection; all received mycophenolate mofetil; and 5/6 had been switched from cyclosporine to tacrolimus because of steroid-resistant rejection. Transient neutropenia (absolute neutrophil count less than 1000) was observed in 2/6; 3/6 had received OKT3 therapy for refractory rejection. These six patients were treated with a combination of antimicrobials, immunoglobulin replacement, and decrease in immunosuppressive therapy.

CONCLUSION

The finding of unexpected hypogammaglobulinemia and concomitant infectious complications in six heart transplant recipients highlights a possible complication in a subset of patients receiving newer immunosuppressive agents. A larger prospective study is underway to determine risk factors for development of post-transplant hypogammaglobulinemia and to assess pre-transplant immune status of these recipients. Monitoring of immunoglobulin levels in high-risk patients receiving intensified immunosuppressive therapy for rejection may help to prevent infectious complications.

Treatment of atopic eczema with oral mycophenolate mofetil

BACKGROUND

Activated T and B lymphocytes are the predominant inflammatory cells in atopic eczema (AE) lesions. Mycophenolic acid, the active form of mycophenolate mofetil (MMF), blocks the proliferative responses of T and B lymphocytes.

OBJECTIVES

In this pilot study, we examined the efficacy of MMF (CellCept(R), Hoffman La Roche, Grenzach-Wyhlen, Germany) in severe AE.

METHODS

Ten patients with severe AE (severity index > 50) according to the Severity Scoring of Atopic Dermatitis (SCORAD) index were treated with oral MMF at an initial dose of 1 g daily during the first week and 2 g daily for a further 11 weeks. Laboratory examination including full blood count, lymphocyte subset analysis, serum immunoglobulins (IgE, IgG, IgM, IgA), total bilirubin, alkaline phosphatase, aminotransferases, lactate dehydrogenase and creatinine was performed every 2 weeks. Additionally, interleukin (IL)-10 and interferon (IFN)-gamma in serum were measured.

RESULTS

None of the 10 patients who received MMF discontinued the trial because of lack of efficacy or adverse events. Compared with the baseline, the median scores for disease severity (SCORAD index) improved by 68% during treatment with MMF. The median serum IgE level decreased significantly, from 10,300 kU L-1 before treatment to 7830 kU L-1 after 12 weeks. MMF induced a significant increase in the T-helper (Th)-1-related cytokine IFN-gamma and a significant decrease in IL-10, mainly produced by Th2 cells.

CONCLUSIONS

The present study demonstrates that oral MMF at a dose of 2 g daily is an effective, safe and well-tolerated immunosuppressive therapy for severe AE in adults.

The use of mycophenolate mofetil in transplant recipients

With the development of new immunosuppressive agents, the focus of anti-rejection therapy has shifted from prevention of acute allograft rejection to an emphasis on sufficient immunosuppression with minimal toxicity. Mycophenolate mofetil (MMF) is a recently developed immunosuppressive drug, which acts to inhibit T and B cell proliferation by blocking the production of guanosine nucleotides required for DNA synthesis. It also prevents the glycosylation of adhesion molecules that are involved in attachment of lymphocytes to endothelium and potentially in leukocyte infiltration of an allograft during an immune response. High-quality randomized clinical trials have demonstrated that MMF, when used with cyclosporine (CsA) and steroids, reduces the frequency and severity of acute rejection episodes in kidney and heart transplants, improves patient and graft survival in heart allograft recipients and increases renal allograft survival at 3 years. It has also been effective in reversing acute and resistant rejection episodes in heart, kidney and liver recipients. The ability of MMF to facilitate sparing of other immunosuppressive agents, particularly in CsA-related nephrotoxicity, is also promising. By permitting reduction in CsA doses, MMF may stabilize or improve renal graft function in patients with CsA-related nephrotoxicity or chronic allograft nephropathy. Early results of phase I and II trials evaluating MMF therapy in liver and combined pancreas/kidney transplant recipients are encouraging. The main adverse effects associated with oral or intravenous MMF are gastrointestinal and hematologic in nature. Although the direct costs of using MMF vs. azathioprine (AZA) are higher, the decreased incidence and treatment of acute rejection in patients treated with MMF supports its use as a cost-effective option during the first year following transplantation.Thus, MMF has become an important therapeutic tool in the transplant clinician's armamentarium. Ongoing issues to be resolved in clinical trials include the role of MMF in the absence of other potent agents, e.g., as monotherapy or with a steroid but without calcineurin inhibitor; whether MMF will have an impact on chronic allograft dysfunction; and the cost-effectiveness of treatment following the first year of transplantation.

Mycophenolate mofetil for maintenance therapy of Wegener's granulomatosis and microscopic polyangiitis: a pilot study in 11 patients with renal involvement

Successful maintenance therapy with mycophenolate mofetil (MMF) 2 g/d and low-dose oral corticosteroids (OCS) over a period of 15 mo was given to patients with Wegener's granulomatosis (WG) (n = 9) and microscopic polyangiitis (MPA) (n = 2). All patients had severe generalized disease with pauci-immune necrotizing glomerulonephritis and received standard induction therapy with oral cyclophosphamide and OCS for a mean of 14 wk until remission was achieved. Of 11 patients, only one WG patient relapsed in the 14th month of maintenance therapy. Maintenance therapy with MMF was able to further reduce grumbling disease activity as measured by the Birmingham vasculitis activity score (BVAS2) and proteinuria that were still present by the end of induction therapy. OCS could be reduced to a median daily dose of 5 mg and discontinued in three patients. Possible drug-related adverse effects were transient and included abdominal pain, respiratory infection, diarrhea, leukopenia, and a cytomegalovirus-colitis in one patient that was successfully treated with ganciclovir. It is concluded that MMF in combination with low-dose OCS is well tolerated and effective for maintenance therapy of WG and MPA. Long-term treatment with MMF in these diseases is attractive because of its low toxicity. MMF will have to be studied further and compared with cyclophosphamide or azathioprine maintenance therapy in randomized trials.

Mycophenolic acid increases apoptosis, lysosomes and lipid droplets in human lymphoid and monocytic cell lines

BACKGROUND

Mycophenolic acid (MPA), a selective inhibitor of inosine monophosphate dehydrogenase, is the active agent of the immunosuppressive drug, mycophenolate mofetil (MMF). Previous studies have shown that MPA inhibits DNA synthesis in T and B lymphocytes by blocking de novo guanosine synthesis, and that MPA induces monocyte differentiation. MMF is being used for prevention of organ graft rejection and has also shown efficacy in rheumatoid arthritis trials. This study was designed to determine if apoptosis also plays a role in the immunosuppressive and anti-inflammatory effects of MMF.

METHODS

Cultured human T lymphocytic (MOLT-4) and monocytic (THP-1 and U937) cell lines were treated with MPA. Apoptosis, cell viability, DNA content, lipid content, cell volume, and lysosomes were measured by a variety of microscopic, flow cytometric, and biochemical techniques.

RESULTS

MPA inhibits proliferation, arrests cell cycle in S phase, and increases apoptosis in all three cell lines. Exogenous guanosine added within 24 hr of MPA treatment, but not later, partially reversed MPA-induced apoptosis in MOLT-4 cells. MPA increased lipid droplets in all three cell lines and increased both cell volumes and numbers of lysosomes in the monocytic cell lines. In both monocytic cell lines, MPA also reduced the number of nuclei containing nucleoli and greatly increased neutral lipids, primarily triacylglycerols, suggesting that these cells were differentiating.

CONCLUSIONS

Increased apoptosis and terminal differentiation of both lymphocytes and monocytes may promote the antiproliferative, immunosuppressive, and anti-inflammatory effects of MMF seen clinically in transplantation and rheumatoid arthritis.

Increased incidence of allograft rejection in stable heart transplant recipients after late conversion from mycophenolate mofetil to azathioprine

Mycophenolate mofetil (MMF) is a safe and effective immunosuppressive agent in kidney and liver transplantation. Preliminary studies also support its use in heart transplantation. However, the cost of MMF is substantially greater than azathioprine (AZA), the current alternative. Since the majority of rejection episodes occur within the first few months of transplantation, using MMF early after transplantation and subsequently converting to AZA, after the risk of rejection has diminished, might be cost-effective. In order to evaluate the safety of such a strategy in heart transplant recipients, we reviewed the rejection profiles of a group of patients who were converted from MMF to AZA late after transplantation. Forty-three stable patients on chronic MMF therapy as part of an open-label, long-term safety study were converted to either commercially available MMF (CellCept) or AZA, at the conclusion of the study. Demographic variables, rejection histories before and after conversion, and immunosuppressive regimens were examined. Twenty-three patients were continued on commercial MMF and 20 were converted to AZA therapy. The average duration of MMF therapy prior to conversion was 41 months in each group. Baseline demographics were similar in the two groups. Treated allograft rejection occurred in 10 of 20 patients converting to AZA, as compared to only 1 of 23 patients remaining on MMF; p = 0.002. Additionally, mean scores (1-5 scale) for the three biopsies before and after conversion favored continued MMF therapy (1.5+/-0.6 before and 1.2+/-0.4 after conversion in MMF group vs. 1.3+/-0.5 before and 1.7+/-0.9 after conversion to AZA; p = 0.02). No allograft loss occurred as a result of conversion. These data suggest that conversion from MMF to AZA, even late after transplantation, can be associated with allograft rejection. The costs associated with these rejection episodes (the additional immunosuppressive agents, endomyocardial biopsies, and physician visits) may exceed the potential cost savings of converting stable heart transplant recipients from MMF to AZA.

The US multicenter double-blind, randomized, phase III trial of thymoglobulin versus atgam in the treatment of acute graft rejection episodes following renal transplantation: rationale for study design

In this study intended to establish equivalence between two antibody therapies for acute rejection in kidney transplant recipients, it was important to develop a rigorous protocol. Assurance of the presence of acute rejection was imperative. Therefore, due to the lack of literature support for clinical assessment of renal dysfunction, histologic diagnosis of acute rejection was required for enrollment in the study. Likewise, supportive literature for a correlation between response to anti-rejection therapy and the severity of rejection lead to the decision that the study should be stratified by a measurement of rejection severity for which Banff criteria were used. Finally, quantification of the response to therapy was also measured against the available literature and a large, newly developed international database of kidney transplant rejection episodes (the Efficacy Endpoints database) where serum creatinine, expressed as a percentage of the baseline level at the time of rejection was shown to be the most effective, available clinical marker of rejection response. Therefore, the US Multicenter Phase III Trial for comparing Thymoglobulin to Atgam in the treatment of acute rejection exhibits a unique and detailed study design that could be implemented in future trials as well as in clinical practice to improve assessment of outcomes.

Immunosuppressive therapy

Although several new immunosuppressive medications have been developed in the past decade, many possible avenues are yet to be explored. Although the newer agents have not reflected any clear benefit in patient or graft survival over CsA or tacrolimus, they have been useful in reducing the incidence and severity of rejection, reducing the concomitant use of steroids, and decreasing the doses of CsA or tacrolimus to minimize their toxicity profile. The appearance of these new agents has given more options to clinicians, who can select the one with the least toxicity and most efficacy for individual patients. In the future, combinations of these agents, in conjunction with a strategy to induce tolerance of the donor organ without drug toxicity, will be the goal.

Synergistic effects of mycophenolate mofetil and sirolimus in prevention of acute heart, pancreas, and kidney allograft rejection and in reversal of ongoing heart allograft rejection in the rat

BACKGROUND

The effect of mycophenolate mofetil (MMF) and sirolimus (rapamycin, RAPA) mono- and combination-therapy was examined in prevention of acute heart, pancreas, and kidney allograft rejection and in reversal of ongoing heart allograft rejection in the rat.

METHODS

Both drugs were administered orally for up to 30 days. Eleven groups (n=6) were involved in the first part of the heart allografting model. Brown Norway (RT1n) to Lewis (RT1(1)) combination was used in the heart and pancreas transplantation models, whereas Buffalo (RT1b) to Wistar Furth (RT1u) was used in the kidney transplantation model.

RESULTS

The naive control group showed a mean survival time of 6.5+/-0.6 days. There were graded dose-responses to monotherapy of MMF 10 and 20 mg(kg/ day (12.5+/-2.6 days; 19.3+/-9.0 days) and RAPA 0.2, 0.4, 0.8, and 1.8 mg/kg/day (19.2+/-2.0 days; 30.0+/-7.3 days; 50.8+/-12.5 days; 51.2+/-2.6 days), respectively (P=0.001). Results with the combined use of drugs indicate that a synergistic or very strong synergistic interaction was produced when compared with monotherapy of MMF or RAPA: MMF 10 mg(kg/day+RAPA 0.2 mg/kg(day (52.7+/-5.7 days, combination index [CI] =0.189), MMF 20 mg(kg/day+RAPA 0.2 mg/kg/day (57.7+/-5.7 days, CI=0.084), MMF 10 mg/kg/day+RAPA 0.4 mg(kg/day (50.2+/-13.5 days, CI=0.453), and MMF 20 mg/kg(day+ RAPA 0.4 mg/kg(day (51.5+/-6.8 days, CI=0.439), respectively. These results were repeatable in the prevention of acute pancreas and kidney allograft rejection in the rat. In the second part of the study of reversal of ongoing acute heart allograft rejection model, the combined treatment of MMF 10 mg/kg(day+RAPA 0.2 mg/ kg(day (35.5+/-16.0 days, CI=0.794) and MMF 20 mg/kg day+RAPA 0.2 mg(kg/day (57.2+/-4.7 days, CI=0.310) represented synergistic interaction compared with monotherapy of MMF or RAPA.

CONCLUSIONS

Concomitant therapy of MMF and RAPA produces a synergistic effect in prevention of heart, pancreas, and kidney allograft rejection and in reversal of ongoing heart allograft rejection in the rat.