Rediscovering mycophenolic acid: a review of its mechanism, side effects, and potential uses

Coexistent psoriasis and bullous pemphigoid responding to mycophenolate mofetil monotherapy

A 73-year-old woman with a 50-year history of psoriasis was referred to our clinic with a 4-month duration of tense bullae on erythematous base and erosions localized on her lower extremities and torso (Figure 1A). Neither the oral nor the ocular mucosa had been involved. The lesions were intensively pruritic, significantly affecting the quality of her life. At the time of the examination, the patient presented with psoriatic plaques with adherent scales confined on the scalp (Figure 2A). According to the patient's history, her limited psoriasis was partially controlled with occasional topical medications (topical corticosteroids, calcipotriol, and tar shampoo). She also had insulin-dependent diabetes mellitus, asthmatic bronchitis, and partially controlled hypertension with hyperlipidemia. A biopsy specimen was taken from lesional skin on her feet, and a histological examination showed a subepidermal blister with an inflammatory cell infiltrate in the upper dermis. No drugs were incriminated, and diagnosis of bullous pemphigoid was confirmed by Western immunoblotting of serum. Laboratory investigation revealed mild thrombocytopenia of 110,000/mm(3), cholesterol 279 mg/dL, and triglycerides 210 mg/dL. The patient could not tolerate prednisolone and cyclosporine because of hypertension and diabetes, or azathioprine because of the mild thrombocytopenia; she did not consent to receiving biologics. Mycophenolate mofetil (MMF) was then considered a choice. The patient agreed, and she was initially administered 1000 mg/d. After 2 weeks, the dosage increased to 1000 mg twice a day because of the formation of new blisters. Within 8 weeks of treatment with MMF 2000 mg/d, marked improvement was observed and her pruritus resolved. Complete remission of bullous pemphigoid and psoriasis was achieved within 3 and 4 months, respectively. Routine laboratory studies were performed before treatment and every month during therapy, and MMF was tolerated without side effects. The treatment was continued for 6 months with no subsequent relapse of the dermatoses (Figure 1B and Figure 2B).

Mycophenolate mofetil prevents lethal acute liver failure in mice induced by bacille Calmette-Guérin and lipopolysaccharide

BACKGROUND/AIMS

To investigate the effect of mycophenolate mofetil (MMF) on acute liver injury induced by bacille Calmette-Guérin (BCG) and lipopolysaccharide (LPS).

METHODS

Acute liver failure was induced in male Kunming strain mice by injecting the animals with BCG 2.5 mg per mouse, and LPS 10 microg per mouse 10 days later. The mice in the treatment groups were given MMF 2 h before, simultaneous with, or 2 h after administration of LPS, and the mice in the control group were given the same dose of saline. The 24-h survival rate, serum alanine aminotransferase (ALT), and aspartate aminotransferase (AST) levels were compared. Serum levels of tumor necrosis factor alpha (TNF-alpha), interferon gamma (IFN-gamma), and interleukin 6 (IL-6) were measured and the expressions of TNF-alpha, IFN-gamma, and IL-6 mRNA in the liver tissue were determined by reverse transcription-polymerase chain reaction (RT-PCR). Concanavalin A (Con A)-induced splenocyte proliferation were determined by methods of methyl thiazolyl tetrazolium.

RESULTS

Injecting a small dose of LPS into BCG-primed mice caused a lethal hepatic injury mimicking acute hepatitis, from which 16 of the 20 mice died within 24 h (20% survival rate). Massive necrosis of parenchymal hepatocytes with marked inflammatory cell infiltration was observed by histological examination. In parallel, serum ALT and TNF-alpha, IFN-gamma, and IL-6 levels were increased. Expression of TNF-alpha, IFN-gamma, and IL-6 mRNA in the liver were significantly increased also. Treatment with MMF markedly reduced the death rate in a dose-dependent manner. It reached its maximal effect at the dosage of 150 mg per kg of body weight when pretreated 2 h before LPS injection, with improvement of histological feather and survival rate (84.2%, 16/19). MMF significantly inhibited serum levels of TNF-alpha, IFN-gamma, and IL-6, and significantly reduced TNF-alpha, IFN-gamma, and IL-6 expression in the liver, which increased after BCG and LPS injection. Moreover, splenocyte proliferation response induced by Con A was also inhibited by MMF treatment.

CONCLUSIONS

Treatment with MMF has a protective effect on endotoxin-induced fatal liver failure by regulating the production of inflammatory cytokines and T-cell proliferation.

Mycophenolate mofetil therapy for refractory inflammatory bowel disease

BACKGROUND

Mycophenolate mofetil (MMF) is an immunomodulatory drug, and its use in inflammatory bowel disease has previously been reported. The aim of this study was to review the Leeds Colitis Clinic experience of the safety and efficacy of MMF in treating patients with refractory Crohn's disease (CD) and ulcerative colitis (UC). This is an extension of a previously published study from our center with a longer follow-up period and approximately twice the number of patients.

METHODS

A retrospective analysis was performed of the records of all patients treated with MMF for inflammatory bowel disease over a 5-year period.

RESULTS

Of 70 patients identified, 67 had previously been treated with azathioprine unsuccessfully. Seventeen of the 70 patients had been successfully maintained in remission with MMF for an average duration of 33 months. Treatment with MMF was discontinued for 53 patients, 17 because of side effects and 36 because they had not responded to the treatment.

CONCLUSIONS

In our series, 17 patients (24.3%) had a sustained steroid-free remission with MMF therapy. Nineteen patients (27%) experienced side effects, of which 17 (24.3% of the total group) had to discontinue therapy. An additional 36 (51.4%) required an escalation in medical therapy or surgery because of failure of the MMF therapy. MMF may have a role in the treatment of refractory inflammatory bowel disease, especially in patients who have previously failed standard therapies such as azathioprine.

Mycophenolate sodium for subacute cutaneous lupus erythematosus resistant to standard therapy

BACKGROUND

Approximately 75-95% of patients with cutaneous lupus erythematosus respond to antimalarial therapy and/or topical glucocorticosteroids. Immunosuppressive agents are usually considered a second-line approach in patients with resistant disease.

OBJECTIVES

This was a prospective, nonrandomized, open pilot study to evaluate the efficacy of mycophenolate sodium monotherapy in patients with recalcitrant subacute cutaneous lupus erythematosus (SCLE).

METHODS

Monotherapy with oral enteric-coated mycophenolate sodium 1440 mg daily was given for a total of 3 months. Treatment outcome was evaluated by means of a validated clinical score for cutaneous lupus erythematosus, the Cutaneous Lupus Erythematosus Disease Area and Severity Index (CLASI), as well as 20-MHz ultrasound measurements and colorimetry. Safety assessment included the monitoring of adverse effects and clinical laboratory parameters.

RESULTS

Ten patients with active SCLE resistant to at least one standard therapy were included in the trial. Mycophenolate sodium led to a remarkable improvement of skin lesions, resulting in a significant decrease of the mean +/- SD CLASI from 10.8 +/- 6.0 at the beginning to 2.9 +/- 2.6 at the end of therapy. Clinical improvement was confirmed by ultrasonographic assessments and colorimetry. No serious side-effects were noted.

CONCLUSIONS

Mycophenolate sodium is beneficial and safe in the treatment of patients with SCLE that failed standard therapy. However, these preliminary data must be confirmed by randomized controlled trials including a larger sample size.

Antiviral activity of tiazofurin and mycophenolic acid against Grapevine leafroll-associated virus 3 in Vitis vinifera explants

The ability to control plant viral diseases with chemicals has great potential value for agriculture, but few chemicals are available to date due to the difficulty in obtaining effective drugs. IMP dehydrogenase is an enzyme which catalyzes the conversion of inosine 5'-monophosphate to xanthosine 5'-monophosphate in the de novo purine nucleotide synthetic pathway, and is considered a sensitive target for antiviral drugs. Two IMPDH inhibitors, tiazofurin (TR) and mycophenolic acid (MPA), were tested for their inhibitory effect on Grapevine leafroll-associated virus 3 (GLRaV-3) in in vitro grapevine explants. TR administration produced plantlets characterized by negative ELISA readings. No PCR products were obtained from these samples. This was confirmed by the absence of viral particles. MPA was essentially ineffective against GLRaV-3 replication in Sangiovese explants. This is the first report of GLRaV-3 eradication in grapevine explants following TR administration.

Optimal management of severe plaque form of psoriasis

Psoriasis is a chronic, inflammatory, hyperproliferative skin disease that affects 1-2% of the general population in the UK and US. Plaque psoriasis is the most common form, accounting for approximately 90% of cases. The disease is usually chronic and persistent, although up to 50% of patients may enter spontaneous remission for varying periods of time. There is no cure for psoriasis; therefore, the aim of treatment is to minimize the extent and severity of the disease to the point at which it no longer substantially disrupts the patient's quality of life. First-line therapy of psoriasis usually consists of topical agents, such as emollients, tar, dithranol, and vitamin D3 analogs. In cases of severe, extensive psoriasis, where topical therapy is either impractical or not sufficiently effective, systemic treatment may be warranted at the outset. In these circumstances, the therapeutic options include: (i) intensive inpatient or day center topical therapy; (ii) phototherapy; and/or (iii) systemic agents. There are now a number of systemic agents available for the treatment of severe psoriasis, but all have potential adverse effects. We review the current treatment options, which include the use of phototherapy and systemic agents, and provide recommendations on their use in clinical practice. Importantly, treatment should be tailored to each individual patient depending on concurrent medical problems (which might preclude certain agents), patient choice and acceptance of the risk of adverse effects.

Emerging drugs in psoriasis

Psoriasis is a relatively common, chronic skin disease affecting 1-2% of the population in the developed countries. It is an inflammatory, autoimmune skin disorder characterised by an accelerated rate of epidermal proliferation and disordered differentiation. Since our last review in 1999, considerable progress has been made in understanding the immunopathogenesis of this disease, and new drugs have become available for its treatment. Recent clinical trials showed the efficacy of novel biotechnology approaches, such as blocking tumour necrosis factor-alpha or T-cell-mediated immune response by the anti-CD2, anti-CD11a, anti-B7, anti-CD4 or anti-CD25 approaches. Agents which block type 1 cytokines or skew immune reactions into type 2 are other promising approaches. Other possible targets are chemokines and their receptors, the cytokines and receptors involved in T cell trafficking into the skin, and peroxisome proliferator-activated receptors. Relatively little development is reported of the drugs targeting the keratinocyte or the classical antipsoriatic compounds which include glucocorticoids, vitamin D derivatives and cytostatic agents.

The Use of Systemic Immune Moderators in Dermatology: An Update

In addition to corticosteroids, dermatologists have access to an array of immunomodulatory therapies. Azathioprine, cyclophosphamide, methotrexate, cyclosporine, and mycophenolate mofetil are the systemic immunosuppressive agents most commonly used by dermatologists. In addition, new developments in biotechnology have spurred the development of immunobiologic agents that are able to target the immunologic process of many inflammatory disorders at specific points along the inflammatory cascade. Alefacept, efalizumab, etanercept, and infliximab are the immunobiologic agents that are currently the most well known and most commonly used by dermatologists. This article reviews the pharmacology, mechanism of action, side effects, and clinical applications of these therapies.

Chronic actinic dermatitis treated with mycophenolate mofetil

Chronic actinic dermatitis (CAD) is a persistent photodermatosis that usually affects elderly men. We report two male patients, aged 55 years (patient A) and 49 years (patient B), who presented with an eczematous eruption on sun-exposed skin. Phototesting revealed a markedly reduced 24-h minimal erythema dose (MED). Both patients had refractory disease and developed significant side-effects to conventional therapies, including topical steroids, prednisolone, psoralen with ultraviolet A, azathioprine and ciclosporin. They had each received at least 6 years of treatment prior to commencing mycophenolate mofetil (MMF). Each noted a significant improvement in symptoms within 6 weeks and subsequent clearing of the eczematous lesions. Patient A still requires continuous treatment with MMF 500 mg twice daily to prevent relapses. Patient B maintains remission by using MMF 1 g twice daily only during the spring and summer months. Both patients have tolerated the treatment well with no abnormalities in blood cell counts or liver biochemistry. Since commencing MMF, their quality of life has significantly improved. These observations suggests that MMF should be considered as an alternative treatment to conventional therapies for refractory CAD.

Combination therapy to treat moderate to severe psoriasis

In patients with moderate-to-severe psoriasis, remission can be difficult to achieve and sustain. Both acutely acting and long-term maintenance agents are needed. Speed and efficiency of available monotherapies tend to be inversely proportional to safety. Combination, rotational, and sequential approaches are often more effective and safer than single-agent therapy. Combining agents with complementary adverse effect profiles is preferable. Apparent synergistic enhancement is seen with most paired combinations of the four major therapies: acitretin, phototherapy (ultraviolet B/psoralen plus ultraviolet A), cyclosporine, and methotrexate. Of those, only cyclosporine in combination with psoralen plus ultraviolet A is contraindicated because of increased cancer risk. Combinations of each of those major therapies with topical agents (retinoids, steroids, vitamin D derivatives, and others) have been used with varying efficacy and safety. The immunomodulators, hydroxyurea and thioguanine, have also shown some success in combination therapy. The new biologic agents with their novel modes of action and adverse effect profiles may prove to be important adjuncts in combination/rotational/sequential approaches. In some cases, monotherapy (with either systemic agents or phototherapy) adequately controls moderate to severe disease. A regimen using a single agent has the advantages of lower cost and greater adherence by the patient. For any number of reasons, however, including loss of efficacy, adverse effects, or cumulative or acute toxicity-and especially the inability to clear resistant lesions-a single modality will not be adequate. Using two or more therapies is thus the rule rather than the exception for most patients with moderate-to-severe psoriasis, but picking a combination that serves to balance safety and efficacy needs careful consideration, especially since no evidence-based treatment guidelines exist.

Recent Advances in Treatment Strategies for Atopic Dermatitis

A wide range of different therapeutic regimens are used for atopic dermatitis. Although many treatment modalities are well established worldwide among clinicians, only the minority of these therapy recommendations are based on results of randomised controlled trials (RCTs). To close the gap between such 'generally' recommended therapies and therapies that are based on data from controlled trials, this review focuses not only on the pharmacological and clinical aspects of the currently proven agents, but also on the advantages and disadvantages of therapies that have not yet been completely tested.A review of the available literature concerning the pharmacological profile and also the level of evidence of therapeutic efficacy of all currently known topical and systemic agents for the treatment of atopic dermatitis reveals a large gap between the knowledge concerning the pharmacological action in vitro and the evidence of clinical efficacy in many cases. We agree with the conclusion of previous reviews that numerous therapies for atopic dermatitis urgently require more independent RCTs and especially comparative trials (e.g. corticosteroids vs calcineurin inhibitors). These are required in order to facilitate the choice of therapeutic strategy for the individual treatment of atopic dermatitis, with its broad spectrum of clinical manifestations and potential complications in adult patients and, particularly, in children.Finally, we also review preclinical trials with several new drugs. Immunomodulators appear to promise a new dimension for the future of therapy for atopic dermatitis, especially for severe and otherwise refractory forms or as alternatives to corticosteroids, that is, to treat facial atopic eczema without the risk of adverse effects.

Management of squamous cell carcinoma in organ transplant recipients

The number of skin cancers continues to rise with well over one million cases of skin cancer expected in the United States this year. Optimal management depends on early detection and treatment. The consequences of skin cancer may be particularly devastating in organ transplant recipients. In this article, management of squamous cell carcinoma in the organ transplant recipient is discussed.

An evaluation of the usefulness of mycophenolate mofetil in pemphigus

BACKGROUND

Pemphigus is a group of autoimmune blistering diseases of the skin and/or mucous membranes requiring management with immunosuppressive therapy. The optimal therapeutic regimen would rapidly induce remission and maintain effectiveness with minimal adverse effects in the long term.

OBJECTIVES

The present study describes our experience of the addition of mycophenolate mofetil (MMF) to prednisolone in the management of severe, refractory pemphigus.

METHODS

Patients with active, refractory pemphigus were treated with MMF. Our series included 12 cases of pemphigus vulgaris, four cases of pemphigus foliaceous and one case of paraneoplastic pemphigus. All patients were monitored to assess disease control and mycophenolate toxicity.

RESULTS

Of the 17 cases, MMF has been of benefit to 12. MMF was well tolerated and there were no treatment withdrawals because of safety concerns.

CONCLUSIONS

We found that MMF permitted a reduction in prednisolone dosage without disease relapse.

Effective treatment of relapsing idiopathic nodular panniculitis (Pfeifer-Weber-Christian disease) with mycophenolate mofetil

Relapsing idiopathic nodular panniculitis is the term used to describe a group of diseases that presents as subcutaneous inflammatory nodules, fever and systemic symptoms and histopathologically displays inflammation within the fat lobules. There is no specific test for diagnosis and extensive investigations are required to exclude systemic causes of panniculitis. No uniform effective therapy is available and various drugs used include mainly corticosteroids alone or in combination with other immunosuppressive agents. Presented in this paper is an intractable case of idiopathic nodular panniculitis whose corticotherapy failed and could not be continued because of serious adverse effects. The rapid and good therapeutic response of the patient to mycophenolate mofetil monotherapy is discussed.

Treatment of cicatricial pemphigoid with mycophenolate mofetil as a steroid-sparing agent

BACKGROUND

Cicatricial pemphigoid (CP) is a rare autoimmune bullous disease that affects the skin and mucous membranes. It commonly ends by serious complications such as blindness, stenosis, and stricture formation and is difficult to treat. Mycophenolate mofetil has been reported to be effective in the treatment of pemphigus vulgaris, pemphigus foliaceus, and bullous pemphigoid either as monotherapy or as a steroid-sparing agent.

OBJECTIVE

Our purpose was to evaluate the effectiveness of mycophenolate mofetil as a steroid-sparing agent in treating patients with CP.

METHODS

Three patients with CP were treated with mycophenolate mofetil and prednisolone.

RESULTS

All 3 patients responded very well to the therapy. None of them showed relapse of the disease for a follow-up period of 6 to 14 months after complete cessation of mycophenolate mofetil and prednisolone. No side effects were seen.

CONCLUSION

Mycophenolate mofetil appears to be a safe and effective steroid-sparing agent in the treatment of CP.

Quantification of mycophenolate mofetil in human skin extracts using high-performance liquid chromatography-electrospray mass spectrometry

A sensitive and selective method for the quantification of mycophenolate mofetil and its active metabolite mycophenolic acid in different human skin layers after dermal administration is presented. The skin layers were separated after in vitro penetration experiments and a methanolic extraction was performed. Positive ion electrospray HPLC-MS in selected ion monitoring mode was used to quantify the substances after isocratic separation by a C18 analytical column. The minimum detectable concentrations were 850 pg/ml for MMF and 1 ng/ml for MPA. The peak areas depended linearly on the concentration of both drugs over the range of 25-1,000 ng/ml (r2 > or = 0.996) with accuracy < or =9.8% and precision < or = 13.2%. Total imprecision at quantification limits was 15.2% at 10 ng/ml and 16.3% at 1,500 ng/ml for MMF and 15.1% at 21.0 ng/ml and 17.5% at 1,300 ng/ml for MPA. This HPLC-MS method will be applicable to the profiling of MMF amounts in skin and its conversion to MPA after application of different formulations.

Mycophenolate mofetil as a systemic antipsoriatic agent: positive experience in 11 patients

BACKGROUND

Mycophenolate mofetil (MMF) is a novel immunosuppressive drug. Several case reports have suggested that MMF has a beneficial effect in patients with psoriasis and autoimmune dermatoses.

OBJECTIVES

To investigate the efficacy and safety of oral MMF in severe psoriasis.

METHODS

Eleven patients with severe stable plaque-type psoriasis and a Psoriasis Area and Severity Index (PASI) between 12 and 53 (mean 30.5) were included in the study. They received oral MMF 1 g twice daily for 3 weeks and then 0.5 g twice daily for 3 weeks. The PASI were determined at baseline (week 0) and after 1, 2, 3 and 6 weeks of treatment.

RESULTS

Within 3 weeks of this therapy there was a reduction in PASI of between 40% and 70% in seven of 11 patients, and only one patient achieved a reduction in PASI of < 25% from baseline (mean PASI 15.6). Reducing MMF from 2 g daily to 1 g daily led to further, although only slight, improvement in six of 11 patients during the following 3 weeks. In four of 11 patients, the PASI increased at this lower dosage, and in one patient the drug was withdrawn because of muscle pain, which was possibly drug induced. This side-effect reversed within a few days after stopping the drug. Other side-effects, especially gastrointestinal and haematological toxicity, were not observed in any of the 11 patients treated. Overall, the mean PASI was 16.1 after 6 weeks.

CONCLUSIONS

We conclude that the immunosuppressant MMF 2 g daily is effective and safe in the treatment of severe psoriasis.

Antimetabolites and cytotoxic drugs

Mycophenolic mofetil, azathioprine, thioguanine, methotrexate, and cyclophosphamide were initially used for the treatment of malignancies. Because of their immunosuppressive activity, the range of diseases responsive to these medications has expanded to include various autoimmune-related diseases. Discussion includes a historical perspective of each medication, recent updates on responsive dermatologic conditions, dosages, monitoring guidelines, and medication expense.

Systemic therapy of atopic dermatitis

Atopic dermatitis is a chronic, relapsing, inflammatory skin disease. Topical therapy is the mainstay, but patients with widespread moderate to severe atopic dermatitis may require systemic therapy. Immunosuppressants, immune response modifiers, antihistamines and antibiotics are among the classes of systemic medications frequently used to treat extensive atopic dermatitis; the indications and scientific support for the use of these and other less commonly used medications will be reviewed in this article.

Successful in vivo blockade of CD25 (high-affinity interleukin 2 receptor) on T cells by administration of humanized anti-Tac antibody to patients with psoriasis

BACKGROUND

Daclizumab is a humanized antibody to the alpha-subunit (CD25) of the interleukin 2 (IL-2) receptor that blocks normal IL-2 binding to this receptor. Because IL-2 is a major stimulus for T-cell growth, blockade of the IL-2 receptor could be useful in treating T-cell-mediated (autoimmune) diseases.

OBJECTIVE

Our purpose was to determine whether adequate concentrations of antibody were achieved in circulating blood and in psoriatic skin lesions to saturate CD25 receptors. We also intended to measure clinical effect and safety of this agent when used alone (without other immunosuppressive drugs) in psoriasis.

METHODS

Nineteen patients with psoriasis in two centers received daclizumab at an initial dose of 2 mg/kg, then 1 mg/kg at weeks 2, 4, 8, and 12. To determine whether CD25 was blocked in vivo, flow cytometric studies measured (1) expression of CD25 on CD3(+) T cells derived from blood and (2) immuno-histochemistry measures of CD25(+) cells done on pretreatment and posttreatment biopsy specimens. Patients were followed up clinically with photographs and Psoriasis Area and Severity Index scores.

RESULTS

This study showed a consistent blockade of CD25 in peripheral blood and tissue during the first 4 weeks of therapy while the dosing was every 2 weeks. Variable desaturation of receptors began after 4 weeks, which correlated with a reversal in disease improvement. Patients with a pretreatment Psoriasis Area and Severity Index score of less than 36 showed a mean reduction in severity by 30% at 8 weeks (P =.02). During the 16 weeks of treatment, a 44.8% decrease in expression of the IL-2 receptor alpha-subunit was found. The absolute T-cell counts were calculated and showed no significant changes during the course of the study. No significant adverse events were produced by daclizumab during this study.

CONCLUSION

We therefore conclude that daclizumab is a well-tolerated agent that blocks CD25 expression in peripheral blood and skin. Furthermore, it may be useful in treating psoriasis in some patients.

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 structure of inosine 5'-monophosphate dehydrogenase and the design of novel inhibitors

The enzyme IMPDH is a homotetramer of approximately 55 kDa subunits and consists of a (beta/alpha)(8) barrel core domain and a smaller subdomain. The active site has binding pockets for the two substrates IMP and NAD. The enzymatic reaction of oxidation of IMP to XMP proceeds through a covalent mechanism involving an active site cysteine residue. This enzyme is a target for immunosuppressive agents because it catalyzes a key step in purine nucleotide biosynthesis which is important for the proliferation of lymphocytes. Several X-ray structures of inhibitors bound to IMPDH have been published. The uncompetitive IMPDH inhibitor MPA is the active metabolite of the immunosuppressive agent mycophenolate mofetil (CellCept(R)) which is approved for the prevention of acute rejection after kidney and heart transplantation. The bicyclic ring system of MPA packs underneath the hypoxanthine ring of XMP*, thereby trapping this covalent intermediate of the enzymatic reaction. Ribavirin monophosphate, the active metabolite of the antiviral agent ribavirin, is a substrate mimic of IMP. The structure of the two inhibitors 6-Cl-IMP and SAD binding in the IMP and NAD pockets of IMPDH, respectively, gives information for the binding mode of the di-nucleotide cofactor to the enzyme. At Vertex Pharmaceuticals a structure-based drug design program for the design of IMPDH inhibitors was initiated. Several new lead compound classes unrelated to other IMPDH inhibitors were found. Integrating structural information into an iterative drug-design process led to the design of VX-497. VX-497 is a potent uncompetitive enzyme inhibitor of IMPDH. The phenyl-oxazole moiety of the molecule packs underneath XMP*, analogous to MPA. VX-497 also makes several new interactions that are not observed in the binding of MPA. VX-497 is a potent immunosuppressive agent in vitro and in vivo. A Phase I clinical trial has been successfully concluded and the compound is currently in Phase II trials in psoriasis and hepatitis C. The rapid progress from initiation of the drug design program to a compound entering clinical trials illustrates the power of structure-based drug design to accelerate the drug discovery process. The structural information on IMPDH has also significantly increased our knowledge about the mechanistic details of this fascinating enzyme.

Treatment of chronic plaque-stage psoriasis and psoriatic arthritis with mycophenolate mofetil

Mycophenolate mofetil (MMF), a widely used immunosuppressant in organ transplantation, is a recent addition to the therapeutic armamentarium of autoimmune and inflammatory skin disorders in dermatology. We describe 5 patients with moderate to severe chronic plaque psoriasis and 6 patients with psoriatic arthritis that was refractory to conventional systemic and/or topical antipsoriatic treatment who were treated with MMF monotherapy (2 g/d) in a 10-week study. Although MMF was tolerated well in all patients, only patients with moderate psoriasis and psoriatic arthritis improved with therapy, whereas patients with severe psoriasis did not respond to MMF. Although MMF seems to be effective and safe for blistering autoimmune diseases and pyoderma gangrenosum, our data do not allow optimistic statements on the use of MMF in severe plaque-stage psoriasis. However, MMF may develop into an interesting therapeutic alternative for patients with psoriatic arthritis.

Broad-spectrum antiviral activity of the IMP dehydrogenase inhibitor VX-497: a comparison with ribavirin and demonstration of antiviral additivity with alpha interferon

The enzyme IMP dehydrogenase (IMPDH) catalyzes an essential step in the de novo biosynthesis of guanine nucleotides, namely, the conversion of IMP to XMP. The major event occurring in cells exposed to competitive IMPDH inhibitors such as ribavirin or uncompetitive inhibitors such as mycophenolic acid (MPA) is a depletion of the intracellular GTP and dGTP pools. Ribavirin is approved as an inhaled antiviral agent for treatment of respiratory syncytial virus (RSV) infection and orally, in combination with alpha interferon (IFN-alpha), for the treatment of chronic hepatitis C virus (HCV) infection. VX-497 is a potent, reversible uncompetitive IMPDH inhibitor which is structurally unrelated to other known IMPDH inhibitors. Studies were performed to compare VX-497 and ribavirin in terms of their cytotoxicities and their efficacies against a variety of viruses. They included DNA viruses (hepatitis B virus [HBV], human cytomegalovirus [HCMV], and herpes simplex virus type 1 [HSV-1]) and RNA viruses (respiratory syncytial virus [RSV], parainfluenza-3 virus, bovine viral diarrhea virus, Venezuelan equine encephalomyelitis virus [VEEV], dengue virus, yellow fever virus, coxsackie B3 virus, encephalomyocarditis virus [EMCV], and influenza A virus). VX-497 was 17- to 186-fold more potent than ribavirin against HBV, HCMV, RSV, HSV-1, parainfluenza-3 virus, EMCV, and VEEV infections in cultured cells. The therapeutic index of VX-497 was significantly better than that of ribavirin for HBV and HCMV (14- and 39-fold, respectively). Finally, the antiviral effect of VX-497 in combination with IFN-alpha was compared to that of ribavirin with IFN-alpha in the EMCV replication system. Both VX-497 and ribavirin demonstrated additivity when coapplied with IFN-alpha, with VX-497 again being the more potent in this combination. These data are supportive of the hypothesis that VX-497, like ribavirin, is a broad-spectrum antiviral agent.

Use of mycophenolate mofetil in the treatment of paraneoplastic pemphigus

Paraneoplastic pemphigus (PNP) is a rare autoimmune blistering disease with circulating antibodies that bind the cell surface of the epidermis and other non-stratifying epithelia, and immunoprecipitate a complex of four or five proteins (250 kDa, 230 kDa, 210 kDa, 190 kDa and occasionally 170 kDa).1,2 Combinations of immunosuppressive agents are usually required to obtain even partial control of the skin lesions.3 Mucous membrane lesions are refractory to treatment. We describe a patient with PNP whose skin and oral lesions are quiescent following treatment with oral mycophenolate mofetil.

Pemphigus foliaceus successfully treated with mycophenolate mofetil as a steroid-sparing agent

Pemphigus foliaceus is an autoimmune blistering disease of unknown origin with antibodies produced against desmoglein 1, an adhesive protein found in the desmosomal cell junction in the suprabasal layers of the epidermis. The disease is primarily treated with corticosteroids and corticosteroid-sparing immunosuppressive agents. We report a case of pemphigus foliaceus successfully treated with mycophenolate mofetil. It remains to be seen whether this agent has a significant effect on the course of the disease and remission induction.

New and emerging therapies for diseases of the oral cavity

It is obvious from the review of the literature that most treatments for oral diseases such as lichen planus, pemphigoid, and pemphigus are based on case reports, anecdotes, and small uncontrolled studies. Efforts must be made to perform more controlled studies to evaluate the efficacy of new treatments. Small numbers of patients at each site and multiple-drug therapy make this task difficult. Dermatologists should familiarize themselves with the newer immunosuppressive agents available. Use of these drugs requires knowledge of their pharmacokinetics and potential side effects, so that they may be used effectively and safely. Relatively low doses of azathioprine, cyclophosphamide, and cyclosporine should then be added to the dermatologist's armamentarium for the treatment of severe or recalcitrant diseases. Old drugs are resurfacing with new (but often off-label) uses as the underlying mechanisms of disease become understood. Thalidomide and mycophenolate mofetil are two examples of promising drugs for the future of dermatology.

Old, new, and emerging therapies for atopic dermatitis

Atopic dermatitis is the most common skin condition in children under the age of 11 years. The chronic, cyclical, pruritic course of AD exacts a huge financial and emotional toll on its sufferers. Confusion about appropriate skin care and the role of allergic factors further complicates management. Although diligent moisturization and judicious use of topical steroids remain the therapeutic standard, new, effective local and systemic agents are now available, and several promising nonsteroidal products may be available soon.

Widespread plaque psoriasis responsive to mycophenolate mofetil

A woman with a long history of widespread plaque psoriasis unresponsive to and/or intolerant of phototherapy, retinoids, methotrexate and cyclosporin was successfully treated with mycophenolate mofetil. Remission was maintained on doses between 1 and 1.5 g/day for 18 months without adverse effects.

Beneficial effect of the inosine monophosphate dehydrogenase inhibitor mycophenolate mofetil on survival and severity of glomerulonephritis in systemic lupus erythematosus (SLE)-prone MRLlpr/lpr mice

The aim of the present study was to evaluate the therapeutic effect of mycophenolate mofetil (MMF) on the course of disease in SLE-prone MRLlpr/lpr mice. Three-months-old mice displaying clinical symptoms of glomerulonephritis were given MMF (100 mg/kg per day) orally via the drinking water. Control mice received i.p. injections of cyclophosphamide (CYC) (1.8 mg/mouse per week) or saline. Survival, albuminuria and haematuria, immunoglobulin levels and anti-dsDNA antibodies in serum, frequencies of immunoglobulin-producing B lymphocytes and glomerular deposits of immunoglobulin and C3 were analysed. The results showed that MMF treatment significantly prolonged survival and reduced the occurrence of albuminuria and haematuria in MRLlpr/lpr mice. In addition, the number of immunoglobulin-producing B cells and serum levels of IgG and IgG anti-dsDNA antibodies were reduced after MMF and CYC treatment. MMF treatment significantly reduced the extent of deposition of C3 in glomeruli. We conclude that the reduced severity of glomerulonephritis following treatment of lupus-prone mice with MMF was as efficacious as that of CYC. These results warrant clinical trials of MMF in SLE patients with glomerulonephritis.

Mycophenolate mofetil: a new therapeutic option in the treatment of blistering autoimmune diseases

BACKGROUND

Mycophenolate mofetil (MMF), an ester of mycophenolic acid (MPA), was approved by the Food and Drug Administration in 1995 and is currently primarily indicated for the prophylaxis of rejection in renal transplant patients. The drug seems also to be of value in the treatment of psoriasis and rheumatic arthritis. Recently there have been 6 reported cases of successful treatment of blistering autoimmune diseases with MMF in combination with high dose prednisone therapy.

OBJECTIVE

On the basis of these reports we administered this new treatment regimen to several patients with blistering autoimmune diseases. Besides using a combination of MMF and high-dose prednisone we wanted to evaluate whether MMF monotherapy is also effective in the treatment of blistering autoimmune diseases.

METHODS

We administered MMF to 5 patients who had severe pemphigus vulgaris or bullous pemphigoid. Two patients received MMF in combination with high-dose prednisone therapy and 3 patients received MMF monotherapy. To our knowledge, this is the first report of successful treatment of pemphigus vulgaris and bullous pemphigoid with MMF monotherapy.

RESULTS

All patients were completely free of symptoms within 8 to 11 weeks of therapy. Patients who had received MMF monotherapy responded as well to treatment as those who received a combination of MMF and high-dose prednisone.

CONCLUSION

Our experiences strongly suggest that MMF monotherapy may be effective for patients even with severe pemphigus vulgaris and bullous pemphigoid. In addition, MMF monotherapy, at least over the short term, offers the advantage of fewer side effects in comparison to immunosuppressive combination therapy and was well tolerated by our patients.

Treatment of autoimmune blistering diseases

The treatment of autoimmune blistering diseases remains therapeutically challenging. Significant improvement in the management of autoimmune bullous diseases has occurred as a consequence of improvements in our ability to predict, monitor, and treat the deleterious effects associated with the drugs used to treat these conditions and the introduction of new agents with lower toxicity. Examples include improvements in monitoring and preventing osteoporosis in patients on long-term systemic corticosteroids, the detection of those at risk for azathioprine toxicity bowing to low thiopurine methyltransferase activity, and the addition of agents such as mycophenolate mofetil and IVIG to our therapeutic armamentarium. These advances offer the promise of improved disease control with fewer side-effects and long-term toxicity for our patients.

Mycophenolate mofetil in autoimmune and inflammatory skin disorders

Mycophenolate mofetil (MMF) has been widely used as an immunosuppressant in organ transplantation. MMF has recently been added to therapeutic regimens for skin disorders. Expanding the use of MMF in dermatology, we describe additional patients with autoimmune and inflammatory skin diseases, including 4 cases of pemphigus vulgaris, 1 case of pemphigus foliaceus, 1 case of perineal and metastatic cutaneous Crohn's disease, 1 case of bullous pemphigoid and psoriasis, and 1 case of psoriasis. Most of these patients had refractory disease or had developed significant side effects to conventional therapy, including azathioprine, methotrexate, prednisone, cyclosporine, acitretin, PUVA, UVB, and tacrolimus. MMF was effective and well tolerated in all these patients. The dosages of MMF ranged from 500 mg twice daily (for psoriasis and Crohn's disease) to 1250mg twice daily (for 3 of 4 patients with pemphigus vulgaris). MMF is an effective and relatively safe immunosuppressant in autoimmune and inflammatory skin diseases.

Mycophenolate mofetil: therapeutic applications in kidney transplantation and immune-mediated renal disease

The immunosuppressant mycophenolate mofetil (MMF) inhibits the enzyme inosine-5' monophosphate dehydrogenase and thus interferes with cellular GTP synthesis. MMF suppresses the cellular and humoral immune response and has antiproliferative effects on vascular smooth muscle and mesangial cells in vitro and in vivo. In large multicenter trials with almost 1500 patients MMF has been proven highly efficacious for transplant rejection prophylaxis with the main side-effects of gastrointestinal disorders and a slightly increased incidence of viral infections. Recent investigations suggest MMF as an alternative immunosuppressant in cyclosporin A nephrotoxicity. Preliminary observations show promising results for MMF in the treatment of autoimmune-mediated renal disease. The rationale for its use in this patient group and evidence from experimental studies are discussed. As current therapy of this disease entity is still unsatisfactory, future clinical trials are necessary to investigate the efficacy and safety of MMF for this new indication.

Cyclosporine consensus conference: with emphasis on the treatment of psoriasis

Cyclosporine has been in worldwide use for 15 years for patients who have undergone transplantation operations and is now being used to control inflammatory reactions in other organs (eg, joints, bowel, and skin). Neoral, a more consistently absorbed form of cyclosporine, has recently been approved by the Food and Drug Administration for the treatment of psoriasis. This report outlines the indications, contraindications, dosage recommendations, monitoring requirements, adverse events, drug interactions, interactions with other psoriasis treatments, and suggestions for cyclosporine's use in rotational therapy.

Candida is not involved in the development of of periungual psoriatic lesion

Infection can be a trigger or an aggravating factor in psoriasis, and in particular, bacterial focal infection is well documented to exacerbate psoriasis presumably through its superantigen. Since fungi could produce superantigen as well, and periungual involvement is often seen in psoriatic patients, we examined if local Candida infection plays some pathogenetic role or not in periungual lesions. In 15 psoriatic patients with periungual involvement, Candida infection was examined by microscopic study, culture, and antifungal treatment. We found no evidence suggestive of the relationship between Candida and psoriatic changes in periungual area.