Impact of gastrointestinal-related side effects on mycophenolate mofetil dosing and potential therapeutic strategies

Prevalence of mycophenolate mofetil discontinuation and subsequent outcomes in pediatric kidney transplant recipients: A PNRC study

BACKGROUND

Mycophenolate Mofetil (MMF) is an effective immunosuppressant used in kidney transplant recipients to prevent acute rejection. Complications such as diarrhea, leukopenia, and infections may necessitate the reduction or discontinuation of MMF. The objective of the study was to investigate the prevalence, timing, and reasons for MMF discontinuation and its association with outcomes in pediatric kidney transplant recipients.

METHODS

Seven Pediatric Nephrology Research Consortium (PNRC) centers participated in a retrospective analysis of kidney transplant recipients <21 years of age. Characteristics and outcomes of patients in whom MMF was discontinued were compared to those who continued taking MMF throughout the first 2 years post-transplant.

RESULTS

The study population included 288 participants (mean age 11.2 years) from 7 North American transplant centers. MMF was discontinued in 93/288 (32%) of participants. Common reasons for discontinuation included infections (35%), diarrhea (32%), leukopenia (15%), and others (18%). Increased cumulative alloimmunity (55% vs. 42%, p = .02), increased number of hospitalizations (82% vs. 67%, p = .01), and viral replications (79% vs. 47%, p < .0001) were observed in the MMF discontinuation group compared to the continuation group. Greater eGFR decline also occurred in the MMF discontinuation group over 2 years of follow-up (-7 vs. -1 mL/min/1.73 m2 , p = .05).

CONCLUSIONS

Almost a third of pediatric kidney transplant recipients who begin MMF for maintenance immunosuppression have it discontinued within the first 2 years post-transplant, and this subset of patients is more likely to experience adverse outcomes. New strategies are needed to manage MMF therapy and improve post-transplant outcomes.

Co prescription of anti-acid therapy reduces the bioavailability of mycophenolate mofetil in systemic sclerosis patients: A crossover trial

OBJECTIVE

Mycophenolate mofetil (MMF) is an effective treatment option for interstitial lung disease (ILD) in systemic sclerosis (SSc). Many patients require co-administration of proton pump inhibitors (PPI) or H2 receptor blockers (HRB) because of various gastrointestinal (GI) manifestations in SSc. Co-treatment with PPI or HRB have shown to reduce serum drug levels in post-transplant patients. We wanted to see if there is a similar phenomenon for Mycophenolate in SSc.

METHODS

Twenty SSc patients, who were on a stable dose of MMF (1.5-3 g) underwent a sequential cross over study with MMF alone in the first month, followed by co-treatment with Ranitidine and then Esomeprazole in the second and third month respectively. Estimation of 12-hour area under curve (AUC) of Mycophenolic Acid (MPA) levels and total GI score were calculated at the end of each month and compared between the treatment arms. [Trial registration: CTRI/2020/06/025,939] RESULTS: Co-administration of esomeprazole was associated with 32.7% (mean difference = 22.28 μg h ml-1) reduction in mean AUC MPA, whereas ranitidine caused a reduction of 21.97% (mean difference = 14.93 μg h ml-1) in MPA AUC when compared to MMF without anti-acid therapies. The addition of ranitidine or esomeprazole resulted in significant reduction in the total GI score.

CONCLUSION

Co-administration of PPI or HRB can significantly reduce the bioavailability of MMF in patients with SSc. To avoid therapeutic failure of MMF drug level monitoring is essential when these agents are co-prescribed with MMF.

Drug-Associated Gastropathy: Diagnostic Criteria

Drugs are widely used to treat different diseases in modern medicine, but they are often associated with adverse events. Those located in the gastrointestinal tract are common and often mild, but they can be serious or life-threatening and determine the continuation of treatment. The stomach is often affected not only by drugs taken orally but also by those administered parenterally. Here, we review the mechanisms of damage, risk factors and specific endoscopic, histopathological and clinical features of those drugs more often involved in gastric damage, namely NSAIDs, aspirin, anticoagulants, glucocorticosteroids, anticancer drugs, oral iron preparations and proton pump inhibitors. NSAID- and aspirin-associated forms of gastric damage are widely studied and have specific features, although they are often hidden by the coexistence of Helicobacter pylori infection. However, the damaging effect of anticoagulants and corticosteroids or oral iron therapy on the gastric mucosa is controversial. At the same time, the increased use of new antineoplastic drugs, such as checkpoint inhibitors, has opened up a new area of gastrointestinal damage that will be seen more frequently in the near future. We conclude that there is a need to expand and understand drug-induced gastrointestinal damage to prevent and recognize drug-associated gastropathy in a timely manner.

Nutrition Disturbances and Metabolic Complications in Kidney Transplant Recipients: Etiology, Methods of Assessment and Prevention-A Review

Nutrition disturbances occur at all stages of chronic kidney disease and progress with the decrease of the kidney filtration rate. Kidney transplantation (KTx) as the best form of kidney replacement therapy poses various nutritional challenges. Prior to transplantation, recipients often present with mild to advanced nutrition disturbances. A functioning allograft not only relieves uremia, acidosis, and electrolyte disturbances, but also resumes other kidney functions such as erythropoietin production and vitamin D3 metabolism. KTx recipients represent a whole spectrum of undernutrition and obesity. Since following transplantation, patients are relieved of most dietary restrictions and appetite disturbances; they resume old nutrition habits that result in weight gain. The immunosuppressive regimen often predisposes them to dyslipidemia, glucose intolerance, and hypertension. Moreover, most recipients present with chronic kidney graft disease at long-term follow-ups, usually in stages G2-G3T. Therefore, the nutritional status of KTx patients requires careful monitoring. Appropriate dietary and lifestyle habits prevent nutrition disturbances and may improve kidney graft function. Despite many nutritional guidelines and recommendations targeted at chronic kidney disease, there are few targeted at KTx recipients. We aimed to provide a brief review of nutrition disturbances and known nutritional recommendations for kidney transplant recipients based on the current literature and dietary trends.

Review article: drug-induced small bowel injury

BACKGROUND

Drug-induced gastrointestinal injury has been increasingly reported, but its exact incidence is not known. The small and large intestines represent the most affected sites of injury, accounting for 20%-40% of all gastrointestinal side effects.

AIM

To provide an updated literature review detailing medications linked to the development of small bowel injury.

METHODS

We conducted a literature search on PubMed from its inception to May 1, 2021. We included English-language original studies, meta-analyses, systematic reviews, review articles and case reports.

RESULTS

Drug-induced enteropathy can range from asymptomatic histological changes resulting in a subtle, self-limited disease to a chronic inflammatory condition mimicking inflammatory bowel disease, or bowel perforation. Endoscopy can demonstrate erythema, mucosal friability, oedema, erosions, ulcers or strictures in severe cases. Histology may include mucosal erosions and ulcerations, focal active enteritis, villous atrophy, epithelial apoptosis or necrotising enteritis. A well-established association has been found with the use of nonsteroidal anti-inflammatory drugs, immunosuppressants, chemotherapeutic agents, antibiotics, immunotherapies, etanercept and olmesartan. Possible associations have been reported with other biologic agents, medications used for glycemic control, antihypertensives, cholinesterase inhibitors, potassium and iron supplements, with conflicting data regarding contraceptives/hormonal therapy and isotretinoin.

CONCLUSION

Physicians should be aware of the manifestations of drug-induced enteropathy as early recognition can lead to prompt discontinuation of the offending therapy and, therefore, a reduced risk of future complications.

Antiproliferatives and Transplantation

Antiproliferative agents include Mycophenolic acid and Azathioprine (which is less commonly used unless in certain conditions). They were initially identified for use in autoimmune and cancer research due to their role in disruption of cellular replication. They have now become the cornerstone of antirejection maintenance therapy in solid organ transplant. In this chapter we will describe the major times that lead to discovery, mechanisms of action, side effects, use during pregnancy and the major clinical trials.

Efficacy and Safety of Switching to Azathioprine for Mycophenolate-Induced Diarrhea in Renal Transplant Recipients

BACKGROUND

Diarrhea is a common adverse effect of mycophenolate treatment in renal transplant recipients. In patients with mycophenolate-induced diarrhea, one option is to switch to mycophenolate to azathioprine. In this study, we aimed to define the safety and efficacy of switching from mycophenolate to azathioprine for mycophenolate-related diarrhea in renal transplant recipients.

METHODS

A total of 177 patients, 59 of whom were switched to azathioprine because of diarrhea and 118 of whom comprised a matched control group without diarrhea and continued mycophenolate treatment participated in this study. We analyzed the effect of switching to azathioprine from mycophenolate on amelioration of diarrhea and graft survival.

RESULTS

We observed that 89.8% of patients who switched to azathioprine because of diarrhea had improved diarrhea complaints. Patients switched to azathioprine because of diarrhea had lower glomerular filtration rates (P < .001) and higher proteinuria (P < .001) compared with the control group before the switch. Patients switched to azathioprine compared with a subgroup of 59 control patients were matched to patients switched to azathioprine in terms of baseline renal function and proteinuria in addition to demographic parameters had higher 10-year graft loss compared with patients who continued mycophenolate (P = .03). Particularly in patients with a glomerular filtration rate <30 mL/min at the time of conversion, the risk of early graft loss was high.

CONCLUSIONS

Although switching from mycophenolate to azathioprine was an effective approach to improve diarrhea, this approach is associated with increased risk of graft loss.

Giant Gastric Ulcers: An Unusual Culprit

Mycophenolate Mofetil (MMF) is routinely used immunosuppressant in solid organ transplantation is commonly associated with several gastrointestinal (GI) side effects. Here we present a case of giant gastric ulcer of 5 cm from MMF use post cardiac transplant. CASE DESCRIPTION: A 56-year-old male with history of severe ischemic cardiomyopathy post heart transplant was on immunosuppression with MMF, tacrolimus and prednisone for 5 months. He presented with severe epigastric pain and intermittent episodes of melena for 1 month. His pain radiated to back that is worsened with eating. Associated with loss of appetite, vomiting and 16-pound weight loss in 3 months. He never smoked, drank alcohol or used over the counter pain medications. He was profoundly anemic requiring blood transfusions. EGD performed demonstrated very large clean-based ulcer of 5 cm diameter in the body, smaller ulcer of 8 mm diameter in pre-pyloric region and 5-10 small aphthous ulcers in the gastric body and fundus. Gastric biopsies taken from the ulcer were negative for Helicobacter pylori, cytomegalovirus and malignancy. Flexible sigmoidoscopy revealed non-bleeding inflamed internal hemorrhoids. Consequently, MMF was discontinued and switched to azathioprine. He was treated with twice daily proton pump inhibitor therapy with resolution of abdominal pain, improved appetite and weight gain. DISCUSSION: MMF is well known for common GI side-effects such as nausea, diarrhea, vomiting, ulcers, abdominal pain and rarely gastrointestinal bleeding. Few studies reported 3 to 8% incidence of ulcer perforation and GI bleeding within 6 months. Risk of gastroduodenal erosions is nearly 1.83 times for MMF, with the highest lesions associated with MMF-tacrolimus-corticosteroid combination treatment as seen in our patient. Hypothesis is that GI tract is vulnerable because of dependence of enterocytes on de novo synthesis of purines, which is disrupted by MMF. Typically, upper GI mucosal injuries of mucosal irritation leading to esophagitis, gastritis and/or ulcers are seen. Endoscopy is both diagnostic and therapeutic if bleeding gastric ulcers are noted. Minor complications improve with reduction of drug dose or use of enteric coated preparation if feasible. Discontinuation of the drug is main stay in the management of MMF related ulcer disease. Simple medical treatment with either H2-receptor antagonists, proton-pump inhibitors, coating agents, prostaglandins or combination has proven effective in most cases. Considering excellent results with medical management of ulcer, role of surgery is limited.

Drug-Induced Small Bowel Injury: a Challenging and Often Forgotten Clinical Condition

PURPOSE OF REVIEW

Most drugs are given by the oral route. Oral intake allows direct contact between the drug and the entire GI tract mucosa, exposing it to potential topical damage until absorption. Medication-induced GI symptoms and lesions are therefore commonly encountered in clinical practice. This review will examine the most common drugs or classes of drugs affecting small bowel function and/or structure.

RECENT FINDINGS

Since non-steroidal anti-inflammatory drugs (NSAIDs) are among the most widely used medicines, NSAID enteropathy is highly prevalent and brings about considerable morbidity. Antimicrobials and proton-pump inhibitors profoundly modify intestinal microbiota, affecting gut sensory and motor functions, while other drugs (like iron and gold derivatives) impair intestinal permeability. Olmesartan (and likely ACE inhibitors) induce villous atrophy and consequent malabsorption. Mycophenolate mofetil, cancer chemotherapeutic agents, and immune checkpoint inhibitors cause intestinal inflammation, abdominal pain, and diarrhea. Potassium chloride supplements may induce small bowel ulceration, stenosis, and perforation while the cotraceptive pill and anticoagulants are associated with intestinal ischemia and spontaneous intramural hematoma, respectively. In clinical practice, a deep knowledge of clinical pharmacology and toxicology and a high degree of suspicion of drug-related adverse events are mandatory. Only then, the practicing physician will be able to diagnose medication-induced small bowel lesions correctly and will implement the best strategies to treat them.

Adverse effects of mycophenolic acid in renal transplant recipients: gender differences

Background Mycophenolic acid is widely used immunosuppressive drug, associated with adverse effects which increase patient morbidity and decrease medication adherence. Objective To evaluate the adverse effects in renal transplant recipients under mycophenolate treatment with respect to gender. Setting University Clinical Centre of Nis, Clinic of Nephrology, Serbia. Method This research included 96 renal transplant recipients, who received immunosuppressive regimen, based on tacrolimus or cyclosporin A, prednisone and mycophenolic acid. The high-performance liquid chromatography method combined with protein precipitation was used for the analysis of mycophelate concentration in human plasma. Drug concentration and dose-adjusted concentration were determined with respect to the patients' gender. An adverse effect scoring system developed by nephrologists within the University of Buffalo Nephrology/Transplant Program was used to monitor adverse effects of therapy. Main outcome measure Individual and scores of adverse effects in relation to the dosing regimen and gender. Results Results showed statistically lower dose and concentrations in men compared to the women in our investigation group. Also, female patients demonstrated higher mean scores (cumulative and subscores) within the same dosing regimens of mycophenolic acid. The gastrointestinal score was significantly higher in women who received a dose greater than 720 mg compared to men (0.20 ± 0.12 vs 0.12 ± 0.12). Women demonstrated higher individual adverse effects such as diarrhea and skin changes (41.7 vs 17.0; p = 0.038 and 62.5 vs 30.2; p = 0.037, respectively). Conclusions The results of our research showed that recipients' gender may play an important role in pharmacokinetic profile of mycophenolic acid, suggesting that women had higher concentration of mycophenolic acid and more serious side effects.

Replacement of mycophenolate mofetil with a JAK inhibitor, AS2553627, in combination with low-dose tacrolimus, for renal allograft rejection in non-human primates

In renal transplant patients, using mycophenolate mofetil (MMF) with calcineurin inhibitors (CNIs; cyclosporine and tacrolimus [TAC]) has led to a significant improvement in graft survival. However, reducing or withholding MMF due to its gastrointestinal adverse events increases rejection risk. CNI-sparing strategies are important to avoid CNI-related nephrotoxicity in clinical settings. Here, we investigated AS2553627, a JAK inhibitor replacing MMF in combination with a sub-therapeutic dose of TAC to treat allograft rejection in a monkey model. AS2553627 inhibited proliferation of IL-2 stimulated T cells with little species difference between monkeys and humans. In MMF monotherapy, oral administration of 20 or 40 mg/kg/day prolonged graft survival with median survival times (MSTs) of 16.5 days and 33 days, respectively, whereas untreated animals showed MST of 6 days. In MMF/TAC (1 mg/kg/day, p.o.) combination therapy, pharmacokinetic analysis indicated that MMF 20 mg/kg/day achieved the clinical target AUC_0-24h and prolonged renal allograft survival, with MST of 24 days. Oral administration of AS2553627 0.24 mg/kg/day in combination with TAC significantly prolonged renal allograft survival to MST of >90 days with low plasma creatinine levels. Histopathological analysis revealed that acute T cell-mediated rejection events such as vasculitis and interstitial mononuclear cell infiltration were significantly inhibited in AS2553627/TAC-treated allografts compared with MMF/TAC-treated allografts. All AS2553627/TAC-treated monkeys surviving >90 days exhibited less interstitial fibrosis/tubular atrophy than monkeys in the MMF/TAC group. These results suggest that AS2553627 replacing MMF is an attractive CNI-sparing strategy to prevent renal allograft rejection.

Estimation of Mycophenolic Acid Area Under the Curve With Limited-Sampling Strategy in Chinese Renal Transplant Recipients Receiving Enteric-Coated Mycophenolate Sodium

BACKGROUND

The enteric-coated mycophenolate sodium (EC-MPS), whose active constituent is mycophenolic acid (MPA), has been widely clinically used for organ transplant recipients. However, its absorption is delayed due to its special designed dosage form, which results in difficulty to monitor the exposure of the MPA in patients receiving the EC-MPS. This study was aimed at developing a relatively practical and precise model with limited sampling strategy to estimate the 12-hour area under the concentration-time curve (AUC0-12 h) of MPA for Chinese renal transplant recipients receiving EC-MPS.

METHODS

A total of 36 Chinese renal transplant recipients receiving the EC-MPS and tacrolimus were recruited in this study. The time point was 2 weeks after the transplantation for all the patients. The MPA concentrations were measured with enzyme-multiplied immunoassay technique for 11 blood specimens collected predose and at 0.5, 1, 1.5, 2, 2.5, 3, 4, 6, 8, and 12 hours after the morning dose of EC-MPS. The measured AUC was calculated with these 11 points of MPA concentrations with the linear trapezoidal rule. Limited sampling strategy was used to develop models for estimated AUC in the model group (n = 18). The bias and precision of different models were evaluated in the validation group (n = 18).

RESULTS

C4 showed the strongest correlation with the measured AUC. The best 3 time point equation was 6.629 + 8.029 × C0 + 0.592 × C3 + 1.786 × C4 (R = 0.910; P < 0.001), whereas the best 4 time point equation was 3.132 + 5.337 × C0 + 0.735 × C3 + 1.783 × C4 + 3.065 × C8 (R = 0.959; P < 0.001). When evaluated in the validation group, the 4 time point model had a much better performance than the 3 time point model: for the 4 time point model: R = 0.873, bias = 0.505 [95% confidence interval (CI), -10.159 to 11.170], precision = 13.370 (95% CI, 5.186-21.555), and 77.8% of estimated AUCs was within 85%-115% of the measured AUCs; for the 3 time point model: R = 0.573, bias = 6.196 (95% CI, -10.627 to 23.018), precision = 21.286 (95% CI, 8.079-34.492), and 50.0% of estimated AUCs was within 85%-115% of the measured AUCs.

CONCLUSIONS

It demanded at least 4 time points to develop a relatively reliable model to estimate the exposure of MPA in renal transplant recipients receiving the EC-MPS. The long time span needed restricted its application, especially for the outpatients, but it could be a useful tool to guide the personalized prescription for the inpatients.

The Impact of Total Gastrectomy on Pharmacokinetics in Kidney Transplant Immunosuppressive Drug Regimes: A Case Study

BACKGROUND

Ensuring reliable gastrointestinal drug absorption of orally administered immunosuppressive medications posttransplant is critical to ensuring graft survival.

METHODS

A 66-year-old man of East Asian origin with a previous total gastrectomy was evaluated for living donor kidney transplantation. Pretransplant pharmacokinetic testing was performed to determine the most appropriate posttransplant medication strategy. The Gastrointestinal Quality of Life Index and Gastrointestinal Rating Scale questionnaires were administered to gauge immunosuppressive medication-related side effects in the absence of a stomach.

RESULTS

The patient's ability to absorb cyclosporin, tacrolimus (Tac), enteric-coated mycophenolate sodium (EC-MPS) and sirolimus (SRL) in oral dosage forms was well-preserved. Compared to nongastrectomy reference populations, the rate and extent of absorption of SRL and mycophenolic acid from EC-MPS were similar. The absorption of Tac and cyclosporin was greater than expected. Mycophenolate mofetil did not provide mycophenolic acid absorption as well as EC-MPS. The patient had worsened gastrointestinal symptoms with mycophenolate mofetil or EC-MPS in combination with Tac and cyclosporin, but this was not seen with isolated SRL.

CONCLUSIONS

This case demonstrates that commonly used postkidney transplantation immunosuppressive regimes may be prescribed after total gastrectomy as long as their limitations are noted.

The Immunosuppressant Mycophenolic Acid Alters Nucleotide and Lipid Metabolism in an Intestinal Cell Model

The study objective was to elucidate the molecular mechanisms underlying the negative effects of mycophenolic acid (MPA) on human intestinal cells. Effects of MPA exposure and guanosine supplementation on nucleotide concentrations in LS180 cells were assessed using liquid chromatography-mass spectrometry. Proteomics analysis was carried out using stable isotope labeling by amino acids in cell culture combined with gel-based liquid chromatography-mass spectrometry and lipidome analysis using ¹H nuclear magnetic resonance spectroscopy. Despite supplementation, depletion of guanosine nucleotides (p < 0.001 at 24 and 72 h; 5, 100, and 250 μM MPA) and upregulation of uridine and cytidine nucleotides (p < 0.001 at 24 h; 5 μM MPA) occurred after exposure to MPA. MPA significantly altered 35 proteins mainly related to nucleotide-dependent processes and lipid metabolism. Cross-reference with previous studies of MPA-associated protein changes widely corroborated these results, but showed differences that may be model- and/or method-dependent. MPA exposure increased intracellular concentrations of fatty acids, cholesterol, and phosphatidylcholine (p < 0.01 at 72 h; 100 μM MPA) which corresponded to the changes in lipid-metabolizing proteins. MPA affected intracellular nucleotide levels, nucleotide-dependent processes, expression of structural proteins, fatty acid and lipid metabolism in LS180 cells. These changes may compromise intestinal membrane integrity and contribute to gastrointestinal toxicity.

[Immunosuppression and its use in kidney transplantation]

BACKGROUND

Current immunosuppressive protocols effectively prevent acute rejection of renal allografts. Extensive drug toxicity and the deleterious effects of long-term immunosuppression are associated with significant morbidity and mortality.

OBJECTIVES

The purpose of this article is to provide an overview over modern immunosuppressants and their unwanted side effects and to discuss strategies for improved long-term transplant survival.

METHODS

Review of the current topic-related literature and discussion of our own experience.

RESULTS

The use of antibody induction together with an initial combination therapy of calcineurin inhibitors, mycophenolate and steroids is recommended and results in excellent early outcomes. Detrimental effects include an increased incidence of infections, malignomas, and cardiovascular diseases. Long-term transplant survival is impaired by extensive drug toxicity and the frequent development of donor specific antibodies. Reduction of overall cumulative exposure to immunosuppressants or the reduction of specific toxic drugs such as calcineurin inhibitors and steroids may improve long-term results. Alternative immunosuppressants like mTOR inhibitors and belatacept appear to be effective and safe but their long-term effects on patient and allograft survival needs to be established in clinical trials.

CONCLUSIONS

Current immunosuppressants provide effective protection from renal allograft rejection. However, their use is complicated by serious side effects. In the future, development of novel immunosuppressants and optimization of minimization strategies may help to improve long-term success after kidney transplantation.

Severe Enteropathy From Mycophenolate Mofetil

The adverse effects of mycophenolate mofetil on the colon are well known. However, isolated small intestinal involvement resulting in diarrhea and severe weight loss is infrequently reported in the literature. We present the case of a 45-year-old woman on mycophenolate mofetil following renal transplant, who presented with abdominal pain and weight loss. An esophagogastroduodenoscopy and colonoscopy with biopsies were normal. A small bowel capsule study revealed extensive enteropathy of jejunum and ileum that was confirmed on a push enteroscopy with biopsies. Her symptoms completely resolved after being switched to enteric-coated mycophenolic acid.

Influence of sex and race on mycophenolic acid pharmacokinetics in stable African American and Caucasian renal transplant recipients

BACKGROUND AND OBJECTIVES

No evaluation of sex and race influences on mycophenolic acid (MPA) pharmacokinetics and adverse effects (AEs) during enteric-coated mycophenolate sodium (ECMPS) and tacrolimus immunosuppression are available. The primary objective of this study was to investigate the influence of sex and race on MPA and MPA glucuronide (MPAG) pharmacokinetics in stable renal transplant recipients receiving ECMPS and tacrolimus

METHODS

The pharmacokinetics of MPA and MPAG and their associated gastrointestinal AEs were investigated in 67 stable renal transplant recipients: 22 African American males (AAMs), 13 African American females (AAFs), 16 Caucasian males (CMs), and 16 Caucasian females (CFs) receiving ECMPS and tacrolimus. A validated gastrointestinal AE rating included diarrhea, dyspepsia, vomiting, and acid-suppressive therapy was completed. Apparent clearance, clearance normalized to body mass index (BMI), area under the concentration-time curve from time zero to 12 h (AUC12) and dose-normalized AUC12 (AUC*) were determined using a statistical model that incorporated gastrointestinal AE and clinical covariates.

RESULTS

Males had more rapid apparent MPA clearance (CMs 13.8 ± 6.27 L/h vs. AAMs 10.2 ± 3.73 L/h) than females (CFs 8.70 ± 3.33 L/h and AAFs 9.71 ± 3.94 L/h; p = 0.014) with a race-sex interaction (p = 0.043). Sex differences were observed in MPA clearance/BMI (p = 0.033) and AUC* (p = 0.033). MPA AUC12 was greater than 60 mg·h/L in 57 % of renal transplant recipients (RTR) with 71 % of patients demonstrating gastrointestinal AEs and a higher score noted in females. In all patients, females exhibited 1.40-fold increased gastrointestinal AE scores compared with males (p = 0.024). Race (p = 0.044) and sex (p = 0.005) differences were evident with greater MPAG AUC12 in AAFs and CFs.

CONCLUSION

Sex and race differences were evident, with females having slower MPA clearance, higher MPAG AUC12, and more severe gastrointestinal AEs. These findings suggest sex and race should be considered during MPA immunosuppression.

Diarrhea in solid organ transplant recipients

PURPOSE OF REVIEW

Diarrhea is a common complaint in the solid organ transplant recipient. Unlike the immune-competent patient, diarrhea in an organ transplant recipient may result in dehydration, increased toxicity of medications, and rejection. There is a wide range of causes for diarrhea in transplant recipients, but the most common causes are Clostridium difficile infection, cytomegalovirus, and norovirus. This review will focus on new epidemiology data as to the cause of diarrhea in the transplant population.

RECENT FINDINGS

Recent data have identified C. difficile, cytomegalovirus, and norovirus as important causes of diarrhea in this population, and management should be focused on these causes. Newer diagnostic platforms (such as PCR) are being evaluated, which may help in identification of the cause of diarrhea.

SUMMARY

New epidemiologic data and new testing techniques offer an opportunity for research into better testing strategies for transplant patients with diarrhea. These newer testing strategies may offer better insight into the cause of diarrhea and more appropriate treatment for this illness.

Safety and effectiveness of mycophenolate in systemic sclerosis. A systematic review

Background

Mycophenolate is increasingly being used in the rheumatic diseases. Its main adverse effects are gastrointestinal, myelosuppression, and infection. These may limit use in systemic sclerosis (SSc) since gastrointestinal involvement is common. The objective of this study is to evaluate gastrointestinal adverse events of mycophenolate in SSc. Secondarily we evaluated other adverse events, and the effectiveness of mycophenolate in skin and lung disease.

Methods

A literature search of Medline, Embase, Cochrane Central Register of Controlled Trials, and CINAHL (inception-2013) was performed. Studies reporting use of mycophenolate in SSc patients, adverse events, modified Rodnan skin score (MRSS), forced vital capacity (FVC), or diffusing capacity of carbon monoxide (DLCO) were included. The primary outcome was gastrointestinal events occurring after the initiation of mycophenolate. Secondary safety outcomes included myelosuppression, infection, malignancy, and death after the initiation of mycophenolate.

Results

617 citations were identified and 21 studies were included. 487 patients were exposed to mycophenolate. The mean disease duration ranged between 0.8-14.1 years. There were 18 deaths and 90 non-lethal adverse events. The non-lethal adverse events included 43 (47.7%) gastrointestinal events, 34 (26%) infections, 6 (5%) cytopenias and 2 (2%) malignancies. The most common gastrointestinal events included diarrhea (n=18 (14%)), nausea (n=12 (9%)), and abdominal pain (n=3 (2%)). The rate of discontinuation ranged between 8%-40%. Seven observational studies reported improvement or stabilization in FVC, and 5 studies report stabilization or improvement in MRSS.

Conclusion

Mycophenolate-associated gastrointestinal adverse events are common in SSc, but not severe enough to preclude its use. Observational data suggests mycophenolate may be effective in improving or stabilizing interstitial lung disease, and skin involvement.

Changes in the small bowel of symptomatic kidney transplant recipients converted from mycophenolate mofetil to enteric-coated mycophenolate sodium

BACKGROUND/AIMS

Gastrointestinal (GI) symptoms in renal transplant recipients may be caused due to mycophenolic acid (MPA) toxicity. Using small bowel capsule endoscopy (SBCE) we examined the impact of conversion from Mycophenolate Mofetil (MMF) to enteric-coated formulation of Mycophenolate Sodium (EC-MPS) given to treat GI mucosal lesions.

METHODS

Adult kidney-only recipients at least 30 days after transplant, presenting with GI symptoms while receiving MMF completed a Gastrointestinal Symptom Rating Scale (GSRS) questionnaire, underwent SBCE, and had MMF substituted by EC-MPS. After 30 days, GSRS and SBCE were repeated and findings were compared to baseline values. Patients who were still on EC-MPS 6-24 months post-conversion were contacted for completing a follow-up GSRS questionnaire and SBCE.

RESULTS

Eighteen out of 23 subjects completed the first part of the study. Subjects' median ages and post-transplant time were 47.5 years old and 4.5 months, respectively. Tacrolimus, MMF and prednisone was the main regimen (94%), with a median MMF dose of 750 mg BID. The average baseline GSRS was 2.99 ± 0.81; it significantly decreased to 2.19 ± 0.8 at 30 days post-conversion. At baseline, 50 had gastric and 89% had small bowel lesions. At 30 days, 29 and 62% of the SBCE were still showing gastric and small bowel lesions, respectively. Of 5 patients in the study extension, 4 had abnormal SBCE findings but have been reporting improvement in their symptoms.

CONCLUSION

Stomach and small bowel mucosal lesions are common in kidney recipients with GI symptoms when treated with MMF. Conversion to EC-MPS for 30 days significantly alleviated the GI symptoms; however, no evident correlation with SBCE findings was found.

Concomitant proton pump inhibitors with mycophenolate mofetil and the risk of rejection in kidney transplant recipients

BACKGROUND

Recent pharmacokinetic studies have demonstrated that proton pump inhibitors (PPI) reduce exposure of mycophenolic acid. However, the clinical significance of this drug-drug interaction on transplantation outcomes has not been determined.

METHODS

This was a retrospective cohort study in kidney transplant recipients who were prescribed rabbit antithymocyte globulin, calcineurin inhibitor, mycophenolate mofetil, and steroids. We evaluated the impact of PPI use on the 1-year rates of biopsy-proven acute rejection (BPAR).

RESULTS

Two hundred thirteen patients who were prescribed PPI were compared with 384 patients who were on standard acid-suppressive therapy with ranitidine. BPAR occurred in similar rates in both groups (15% vs. 12%; P=0.31). In a multivariable analysis, black race was associated with a higher risk of rejection (risk ratio [RR], 2.38; 95% confidence interval [CI], 1.41-4.03). While controlling for rejection risk factors, PPI exposure was associated with an increased risk of rejection in black patients (RR, 1.93; 95% CI, 1.18-3.16) but not in non-black patients (RR, 0.54; 95% CI, 0.19-1.49). At 1 year, BPAR type, BPAR grade, patient and graft survival, graft function, and time to BPAR were not associated with PPI exposure.

CONCLUSION

In this retrospective study, PPI use in the first transplant year was associated with an increased risk for BPAR in black patients but not in non-black patients. It is possible that a reduction in mycophenolic acid exposure contributed to the increased risk.

Pharmacology and toxicology of mycophenolate in organ transplant recipients: an update

This review aims to provide an update of the literature on the pharmacology and toxicology of mycophenolate in solid organ transplant recipients. Mycophenolate is now the antimetabolite of choice in immunosuppressant regimens in transplant recipients. The active drug moiety mycophenolic acid (MPA) is available as an ester pro-drug and an enteric-coated sodium salt. MPA is a competitive, selective and reversible inhibitor of inosine-5'-monophosphate dehydrogenase (IMPDH), an important rate-limiting enzyme in purine synthesis. MPA suppresses T and B lymphocyte proliferation; it also decreases expression of glycoproteins and adhesion molecules responsible for recruiting monocytes and lymphocytes to sites of inflammation and graft rejection; and may destroy activated lymphocytes by induction of a necrotic signal. Improved long-term allograft survival has been demonstrated for MPA and may be due to inhibition of monocyte chemoattractant protein 1 or fibroblast proliferation. Recent research also suggested a differential effect of mycophenolate on the regulatory T cell/helper T cell balance which could potentially encourage immune tolerance. Lower exposure to calcineurin inhibitors (renal sparing) appears to be possible with concomitant use of MPA in renal transplant recipients without undue risk of rejection. MPA displays large between- and within-subject pharmacokinetic variability. At least three studies have now reported that MPA exhibits nonlinear pharmacokinetics, with bioavailability decreasing significantly with increasing doses, perhaps due to saturable absorption processes or saturable enterohepatic recirculation. The role of therapeutic drug monitoring (TDM) is still controversial and the ability of routine MPA TDM to improve long-term graft survival and patient outcomes is largely unknown. MPA monitoring may be more important in high-immunological recipients, those on calcineurin-inhibitor-sparing regimens and in whom unexpected rejection or infections have occurred. The majority of pharmacodynamic data on MPA has been obtained in patients receiving MMF therapy in the first year after kidney transplantation. Low MPA area under the concentration time from 0 to 12 h post-dose (AUC0-12) is associated with increased incidence of biopsy-proven acute rejection although AUC0-12 optimal cut-off values vary across study populations. IMPDH monitoring to identify individuals at increased risk of rejection shows some promise but is still in the experimental stage. A relationship between MPA exposure and adverse events was identified in some but not all studies. Genetic variants within genes involved in MPA metabolism (UGT1A9, UGT1A8, UGT2B7), cellular transportation (SLCOB1, SLCO1B3, ABCC2) and targets (IMPDH) have been reported to effect MPA pharmacokinetics and/or response in some studies; however, larger studies across different ethnic groups that take into account genetic linkage and drug interactions that can alter a patient's phenotype are needed before any clinical recommendations based on patient genotype can be formulated. There is little data on the pharmacology and toxicology of MPA in older and paediatric transplant recipients.

Maintenance therapy of lupus nephritis with mycophenolate or azathioprine: systematic review and meta-analysis

OBJECTIVE

The objective of this study was to summarize the comparative efficacy and safety of MMF and AZA as maintenance therapy for LN.

METHODS

Systematic review and meta-analysis of randomized clinical trials of MMF and AZA as maintenance therapy for LN were performed based on a sensitive search. Meta-regression was used to explore causes of heterogeneity. Safety was explored using crude and combined incidence rate ratios (IRRs) of the more frequent adverse events (AEs).

RESULTS

The search produced 7341 hits. Four randomized clinical trials and one long-term study were selected for detailed analysis. No significant differences between MMF and AZA were found in sustained remission, relapse, renal failure, creatinine increase or death. However, there was high heterogeneity in the design of studies, drug doses and treatment in the previous induction phase. Significant lower rates of discontinuation due to AEs occurred in the MMF group, with a relative risk (RR) of 0.60 (95% CI 0.41, 0.88) but significant risk of publication bias (Egger test, P = 0.012). Gastrointestinal manifestations were more common [combined IRR 1.68 (95% CI 1.06, 2.68)] and leucopoenia less frequent in the MMF group [combined IRR 0.14 (95% CI 0.05, 0.42)].

CONCLUSION

The available data does not support the superiority of MMF or AZA as maintenance therapy for LN. Nevertheless, the high heterogeneity of studies included in the analysis makes this contention questionable.

Diarrhea in solid-organ transplant recipients: a review of the evidence

OBJECTIVE

To provide a comprehensive review of the literature as it relates to diarrhea in solid organ transplant (SOT) recipients. In this article, we review the epidemiology, pathogenesis, clinical manifestations, diagnosis and management of diarrhea in SOT recipients and discuss recent advances and challenges.

METHODS

Two investigators conducted independent literature searches using PubMed, Web of Science, and Scopus until January 1st, 2013. All databases were searched using a combination of the terms diarrhea, solid organ transplant, SOT, transplant associated diarrhea, and transplant recipients. Articles that discussed diarrhea in SOT recipients were reviewed and relevant cross-references also read and evaluated for inclusion. Selection bias could be a possible limitation of the approach used in selecting or finding articles for this article.

FINDINGS

Post-transplant diarrhea is a common and distressing occurrence in patients, which can have significant deleterious effects on the clinical course and well-being of the organ recipient. A majority of cases are due to infectious and drug-related etiologies. However, various other etiologies including inflammatory bowel disease must be considered in the differential diagnosis. A step-wise, informed approach to post-transplant diarrhea will help the clinician achieve the best diagnostic yield. The use of diagnostic endoscopy should be preceded by exclusion of an infectious or drug-related cause of diarrhea. Empiric management with antidiarrheal agents, probiotics, and lactose-free diets may have a role in managing patients for whom no cause can be determined even after an extensive investigation.

CONCLUSIONS

Physicians should be familiar with the common etiologies that result in post-transplant diarrhea. A directed approach to diagnosis and treatment will not only help to resolve the diarrhea but also prevent potentially life-threatening consequences including loss of the graft as well. Prospective studies are required to determine the etiology of post-transplant diarrhea in different clinical and geographic settings.

Does reduction in mycophenolic acid dose compromise efficacy regardless of tacrolimus exposure level? An analysis of prospective data from the Mycophenolic Renal Transplant (MORE) Registry

Prospective data are lacking concerning the effect of reduced mycophenolic acid (MPA) dosing on efficacy and the influence of concomitant tacrolimus exposure. The Mycophenolic Renal Transplant (MORE) Registry is a prospective, observational study of de novo kidney transplant patients receiving MPA therapy under routine management. The effect of MPA dose reduction, interruption, or discontinuation (dose changes) was assessed in 870 tacrolimus-treated patients: 375 (43.1%) reduced tacrolimus (≤7 ng/mL at baseline) and 495 (56.9%) standard tacrolimus (>7 ng/mL); enteric-coated mycophenolate sodium 589 (67.7%) and mycophenolate mofetil 281 (32.3%). During baseline to month 1, months 1–3, months 3–6, and months 6–12, 9.3% (78/838), 16.6% (132/794), 20.7% (145/701), and 13.1% (70/535) patients, respectively, required MPA dose changes. These patients experienced an increased risk of biopsy-proven acute rejection at one yr with tacrolimus exposure either included in the model (hazard ratio [HR] 2.60, 95% CI 1.28–5.29, p = 0.008) or excluded (HR 2.58, 95% CI 1.28–5.23, p = 0.008). MPA dose changes were significantly associated with one yr graft failure when tacrolimus exposure was included (HR 2.23; 95% CI 1.01–4.89, p = 0.047) but not when tacrolimus exposure was excluded (HR 2.16; 95% CI 0.99–4.79; p = 0.054). These results suggest that reducing or discontinuing MPA can adversely affect graft outcomes regardless of tacrolimus trough levels.

Increased incidence of endoscopic erosive esophagitis in solid organ transplant recipients

Background/Aims

Solid organ transplant recipients frequently report gastrointestinal symptoms, especially heartburn or dyspepsia. However, the prevalence of endoscopic erosive esophagitis (EE) and associated risk factors after transplantation are unknown. The aim of this study was to determine whether there was a high incidence of endoscopic findings of EE in solid organ transplant recipients.

Methods

This retrospective case-control study included 256 of 3,152 solid organ transplant recipients who underwent sequential screening upper endoscopic examinations and an equal number of controls.

Results

Forty-four (17.2%) and 16 (6.2%) cases of EE were detected in the solid organ transplant and control groups, respectively (p<0.001). In the multivariate analysis, transplantation was significantly associated with EE (odds ratio [OR], 6.48; 95% confidence interval, 2.74 to 15.35). Factors such as old age (OR, 1.17), the presence of a hiatal hernia (OR, 5.84), an increased duration of immunosuppression (OR, 1.07), and the maintenance administration of mycophenolate mofetil (OR, 4.13) were independently associated with the occurrence of EE in the solid organ transplant recipients.

Conclusions

A significant increase in the incidence of endoscopically detected EE was observed in solid organ transplant recipients. This increased incidence was associated with the type and duration of the immunosuppressive therapy.

Enteric-coated mycophenolate sodium in de novo and maintenance kidney-pancreas transplant recipients

BACKGROUND

Our objective was to describe efficacy and safety of enteric-coated mycophenolate sodium (EC-MPS) in de novo and maintenance recipients of kidney-pancreas transplant in the clinical practice.

METHODS

Observational, multicentre, prospective, 12-month study.

RESULTS

We included 24 de novo and 24 maintenance patients. EC-MPS mean (± SD) doses at initiation in de novo patients were 1440 ± 0 vs. 1268 ± 263 mg/d at month 12 (M12). Patient and renal graft survival at one yr were 100%, and pancreatic graft survival was 83.3% (two losses owing to technical failure and two owing to rejection). In the maintenance cohort, EC-MPS was introduced at a median (P25-P75) of 30 (6-71) months after transplant. Baseline doses were 585 ± 310 vs. 704 ± 243 mg/d at M12. In this group, a significant increase in creatinine clearance was observed (65 ± 22 at baseline vs. 74 ± 20 mL/min at M12, p = 0.011). Patient, renal, and pancreatic graft survival were 100%, 95.8%, and 100%, respectively (one kidney graft loss owing to rejection). During follow-up, one patient from each group discontinued EC-MPS.

CONCLUSIONS

The efficacy of EC-MPS in the clinical practice of kidney-pancreas transplantation is good, with high patient and grafts survival at 12 months, and good safety profile. The maintenance group displayed an improvement in renal function.

Tolerance of enteric-coated mycophenolate sodium in combination with calcineurin inhibitor in kidney transplant recipients: Polish experience

INTRODUCTION

Enteric-coated mycophenolate sodium (EC-MPS) was developed to reduce the incidence of gastrointestinal adverse effects. This multicenter observational study was designed to evaluate the safety profile and drug tolerance in kidney transplant recipients.

METHODS

Three hundred adult kidney recipients (median age 48 years) were enrolled over 3 years to receive EC-MPS de novo (n=175), as a switch from azathioprine (n=62) or mycophenolate mofetil MMF (n=63); in combination with calcineurin inhibitor. Drug doses, serum creatinine, estimated glomerular filtration rate (eGFR), as well as drug tolerance, patient and physician evaluation of therapy (on a 4-point scale) were recorded at enrollment and followed over 28 weeks. We modeled the probability of the highest level (ie, best result) of the categorical outcome variable.

RESULTS

Two hundred seventy-three patients completed the study (91%). In the pooled study group (1) best drug tolerance was expected more frequently with tacrolimus versus cyclosporine (odds ratio [OR] 2.12, P<.05); (2) best physician evaluation, with earlier EC-MPS introduction (OR for 4-week delay: 0.99, P<.03) and higher eGFR (OR for 5 mL/min increase: 1.21, P<.01). Among the EC-MPS de novo administrations group: (1) best drug tolerance was expected more frequently with coadministered tacrolimus versus cyclosporine (OR 3.14, P<.02); (2) best patient evaluation, with higher eGFR (OR for 1 mL/min increase: 1.04, P<.04); and (3) best physician evaluation, with higher eGFR (OR for 1 mL/min increase: 1.04, P<.001) and earlier EC-MPS introduction (OR for 4-week delay: 0.99, P<.03). In the conversion from MMF to EC-MPS group: (1) best drug tolerance was expected less frequently with coadministered cyclosporine versus tacrolimus (OR 0.05, P<.04) and more frequently with younger recipients (OR .001, P<.04); (2) best physician evaluation was expected more frequently with lower EC-MPS dose (OR for 360-mg dose increase: 0.4, P<.01) and with higher eGFR (OR for 5 mL/min increase: 1.42, P<.002). Adverse events were reported among 49/300 patients (16 serious adverse events).

CONCLUSIONS

EC-MPS was tolerated better by younger kidney recipients, when combined with tacrolimus versus cyclosporine, and when introduced earlier after transplantation. EC-MPS tolerance decreased gradually with renal function deterioration.

Diagnosis and prevention of chronic kidney allograft loss

Kidney transplantation is the best possible treatment for many patients with end-stage renal failure, but progressive dysfunction and eventual allograft loss with return to dialysis is associated with increased mortality and morbidity. Immune injury from acute or chronic rejection and non-immune causes, such as nephrotoxicity from calcineurin inhibitors, ischaemia-reperfusion injury, recurrent glomerular disease, and allograft BK viral infection, are potential threats. Serial monitoring of renal function enables early recognition of chronic allograft dysfunction, and investigations such as therapeutic drug concentrations, urinalysis, imaging, and a diagnostic biopsy should be undertaken before irreversible nephron loss has occurred. Specific interventions targeting the pathophysiological cause of dysfunction include strengthening of immunosuppression for chronic rejection, or calcineurin inhibitor minimisation, substitution, or elimination if nephrotoxicity dominates. Recommended proactive preventive measures are control of hypertension, proteinuria, dyslipidaemia, diabetes, smoking, and other comorbidities. Strategies to maintain transplant function and improve long-term graft survival are important goals of translational research.

Evalutation of mycophenolic acid systemic exposure by limited sampling strategy in kidney transplant recipients receiving enteric-coated mycophenolate sodium (EC-MPS) and cyclosporine

BACKGROUND

Enteric-coated mycophenolate sodium (EC-MPS) and mycophenolate mofetil (MMF) are prodrugs of mycophenolic acid (MPA). Although many patients still receive MMF as an inosine monophosphate dehydrogenase inhibitor, EC-MPS could be considered a reliable alternative to MMF in the immunosuppressive protocols of kidney transplant recipients. MPA shows high pharmacokinetic variability and consequently a 12-h area under the curve (AUC(0-12)) should be used to guide the therapeutic dosage. However, patient compliance and economic costs make MPA AUC(0-12) an unpractical approach. Limited sampling strategies or predictive systemic drug exposure equation models based on limited sampling times are available only for MMF but lack for EC-MPS.

METHODS

The present study enrolled 26 kidney transplant recipients receiving EC-MPS as part of their immunosuppressive therapy. Twenty-six full MPA AUC(0-12) were performed. By using multiple stepwise regression analysis, we obtained several predictive equations of MPA systemic exposure in this group of patients. The value of the selected equations was tested in a subsequently enrolled group of 26 kidney transplant recipients.

RESULTS

The best equations obtained in the first group of patients were the following: 22.906 + 3.880·C(0) + 1.117·C(1) + 7.527·C(8) (r = 0.901) and 35.064 +3.784·C(0) + 1.002·C(1) + 1.192·C(2) (r = 0.846). These equation models showed an optimal agreement between the full AUCs and estimated AUCs by using the validation group of patients.

CONCLUSIONS

Limited sampling strategies are useful for MPA AUC(0-12) estimation in patients receiving EC-MPS and cyclosporine. The choice of one or the other equation model depends on the pharmacokinetic characteristics of the patients, in particular the potential presence of enterohepatic recirculation.

Biomarkers as a tool for management of immunosuppression in transplant patients

Therapeutic drug monitoring is a well-established approach in transplantation medicine to guide immunosuppressive therapy. However, it cannot always predict the effects of immunosuppressive drugs on immune cells, because it does not reflect any aspect of an individual patient's immune system. Pharmacodynamic monitoring is a more recent strategy to provide information about the biologic effect of a specific drug or drug combination on the individual transplant patient. Currently, there is a large number of different biomarkers that either directly (specific markers) or indirectly (global markers) relate to the pharmacodynamic effects of immunosuppressive drugs and are under investigation as potential candidates to be introduced in clinical practice. Such biomarkers may be useful to identify patients at risk of developing acute rejection, infection, or cancer as well as patients who are suitable for minimization of immunosuppressant therapy and may be helpful to manage the timing and rate of immunosuppressant weaning. Serial longitudinal monitoring may allow maintenance of an individualized immunosuppressive regimen. Thus, biomarker monitoring is a potential complementary tool to therapeutic drug monitoring. This review summarizes the current state of knowledge about the use of a number of global or drug-specific pharmacodynamic biomarkers. It is not a comprehensive overview of the literature available, but rather an evidence-based reflection by experts who are intensively involved in scientific work in this field.

Pharmacokinetic evaluation of mycophenolate mofetil for pemphigus

INTRODUCTION

Pemphigus is an autoimmune blistering disease of the skin and mucous membranes characterized by the development of autoantibodies against the desmosomal proteins, desmoglein-1 and -3. Before the advent of corticosteroids, therapy was almost fatal. The introduction of high-dose corticosteroid therapy has reduced mortality rates to ∼ 10%, but long-term use of steroids can lead to side effects, many of which are severe and associated with significant morbidity. Thus, the major goal of pemphigus therapy has been to reduce the patient's cumulative exposure to systemic corticosteroids. Over the last 2 decades, a range of corticosteroid-sparing immunosuppressive agents have been described, but these therapies are not without potentially serious complications. Despite the range of treatment options, a proportion of patients do not achieve remission, while others show an initial treatment response but remain poorly controlled. The recent availability of mycophenolate mofetil (MMF), originally developed for preventing allograft rejection, appears to be effective in autoimmune blistering diseases in combination with systemic corticosteroid or as a monotherapy.

AREAS COVERED

This review aims to provide an extensive overview of the literature on the clinical pharmacokinetics of MMF in pemphigus treatment and a brief summary of current pharmacodynamic information. After completing this learning activity, readers should be able to summarize the pharmacology of MMF as an immunosuppressant; recognize its potential role in the treatment of pemphigus, including general dosing guidelines and laboratory monitoring schedules, use in patient populations and potential adverse effects; and identify future considerations and developing areas of research regarding the use of mycophenolic acid in the treatment of autoimmune blistering diseases.

EXPERT OPINION

Current morbidity of pemphigus is largely iatrogenic, caused by side effects of the long-term, high-dose corticosteroid therapy that is necessary to sustain disease control. MMF demonstrates complex pharmacokinetics and displays large between-subject pharmacokinetic variability. Experience with MMF has demonstrated long-term safety and tolerability in the treatment of pemphigus.

Safety and tolerance of sodium mycophenolate in patients after renal transplantation--an observational study

BACKGROUND

Enteric-coated mycophenolate sodium (EC-MPS) was developed as an alternative agent to mycophenolate mofetil (MMF), aimed at reduction of gastrointestinal (GI) complications.

METHODS

Seventy-four patients (mean age 42.3 years) switched from MMF to MPS were included in the study and followed-up for 3 months (Visit 0, Visit 2 after 1 month and Visit 3 after 3 months). The mean time from transplantation to switch was 3.7 years. During Visit 2 and 3 the following were recorded: impact of treatment change on the severity of GI symptoms (4 point scale: 1-worsening, 2-no change, 3-improvement, 4-resolution), EC-MPS tolerance, adverse events (AEs), patient compliance and physician satisfaction with treatment (4 point scale: 1-bad, 2-fair, 3-good, 4-very good).

RESULTS

Sixty-three patients completed the study (85.1%). EC-MPS dose ranged from 720 to 1440 mg. GI symptom severity score averaged at 3.41. Symptoms most commonly compelling a conversion were: abdominal pain, diarrhea, abdominal colic, nausea, anorexia and vomiting. Out of 175 complaints, 144 (82%) either improved or resolved, 5 (2.86%) aggravated, and 25 (14.86%) persisted. Patient compliance and mean physician satisfaction score averaged at 3.70 and 3.02 at Visit 3, respectively. 9 AEs (2 severe) were reported. Causal relationship with the medication was suspected in 5 cases (1 case of SAE). The most common AEs were: anemia, infection (including sepsis), GI symptoms (abdominal pain, diarrhea).

CONCLUSIONS

The following was concluded in our study: (1) sodium mycophenolate is well tolerated; (2) after switching from MMF to EC-MPS, gastrointestinal symptoms alleviated; (3) EC-MPS is a safe medication, with a low adverse events rate.