Mycophenolate mofetil and skin diseases

Inhibition of human UDP-glucuronosyltransferase enzyme by Dabrafenib: Implications for drug-drug interactions

Dabrafenib is a novel small molecule tyrosine kinase inhibitor (TKI) which is used to treat metastatic melanoma. The aim of this research was to survey the effects of dabrafenib on human UDP-glucuronosyltransferases (UGTs) and to evaluate the risk of drug-drug interactions (DDIs). The formation rates for 4-methylumbelliferone (4-MU) glucuronide and trifluoperazine-glucuronide in 12 recombinant human UGT isoforms with or without dabrafenib were measured and HPLC was used to investigate the inhibitory effects of dabrafenib on UGTs. Inhibition kinetic studies were also conducted. In vitro-in vivo extrapolation approaches were further used to predict the risk of DDI potentials of dabrafenib via inhibition of UGTs. Our data indicated that dabrafenib had a broad inhibitory effect on 4-MU glucuronidation by inhibiting the activities of UGTs, especially on UGT1A1, UGT1A7, UGT1A8, and UGT1A9, and dabrafenib could increase the area under the curve of co-administered drugs. Dabrafenib is a strong inhibitor of several UGTs and the co-administration of dabrafenib with drugs primarily metabolized by UGT1A1, 1A7, 1A8 or 1A9 may induce potential DDIs.

Management of mycophenolate mofetil-induced acne in patients with Systemic Lupus Erythematosus: report of four cases and review of the literature

Background

Mycophenolate mofetil (MMF) is an immunosuppressive drug currently used to treat Systemic Lupus Erythematosus (SLE). In addition to clinical efficacy, MMF use is also supported by a favorable profile of tolerance, with main side effects being nausea, diarrhea, headache, and, less frequently, leucopoenia. Acne is a relatively frequent adverse reaction to MMF that requires specific treatment and drug suspension.

Investigations

Herein, we describe four cases of MMF-induced acne, none reporting past medical history of acne. The patients were diagnosed with SLE and lupus nephritis and treated with MMF. They developed papulo-pustular and nodular skin lesions consistent with acne. The lesions occasionally showed the appearance of macrocomedones or of unusual, nodular, oedematous lesions in gluteal region, or they had abscess-like features. Culture test demonstrated the presence of Staphylococcus Aureus. They resolved after MMF withdrawal and therapy with tetracycline and local pseudomonic-acid.

Conclusions

Staphylococcus Aureus skin-localized infections inducing inflammatory/infectious acne may be a relatively frequent side-effect of MMF therapy in SLE. As soon as generalized, severe infections, due to Staphylococcus Aureus, may also occur in patients treated with MMF and even if antibiotics therapy is usually relatively effective, at least temporary MMF suspension may be suggested.

Mycophenolate mofetil for severe childhood atopic dermatitis: experience in 14 patients

BACKGROUND

Reports of successful treatment of atopic dermatitis (AD) with mycophenolate mofetil (MMF) have thus far been limited to adults. Considering that the condition typically develops during childhood and is most active during this period, MMF would represent a valuable addition to the therapeutic armamentarium for paediatric AD.

OBJECTIVES

To evaluate the safety and efficacy of MMF in the treatment of severe childhood AD.

METHODS

A retrospective analysis was performed of all children treated with MMF as systemic monotherapy for severe, recalcitrant AD between August 2003 and August 2006 at New York University Medical Center. Fourteen patients meeting these criteria were identified.

RESULTS

Four patients (29%) achieved complete clearance, four (29%) had > 90% improvement (almost complete), five (35%) had 60-90% improvement and one (7%) failed to respond. Initial responses occurred within 8 weeks (mean 4 weeks), and maximal effects were attained after 8-12 weeks (mean 9 weeks) at MMF doses of 40-50 mg kg(-1) daily in younger children and 30-40 mg kg(-1) daily in adolescents. The medication was well tolerated in all patients, with no infectious complications or development of leucopenia, anaemia, thrombocytopenia or elevated aminotransferases.

CONCLUSIONS

This retrospective case series demonstrates that MMF can be a safe and effective treatment for severe, refractory AD in children. MMF represents a promising therapeutic alternative to traditional systemic immunosuppressive agents with less favourable side-effect profiles, and prospective controlled studies are warranted, further to assess its benefits in paediatric AD.

Mycophenolate mofetil in the treatment of uveitis in children

BACKGROUND

Mycophenolate mofetil (MMF) is a new immunosuppressive agent that effectively controls the intraocular inflammation in adults.

PURPOSE

To assess the efficacy of MMF in uveitis in children and to analyse the possible side effects.

PARTICIPANTS AND METHODS

A retrospective analysis was carried out on 17 children (32 eyes) with intraocular inflammation treated with MMF and followed up at the University Eye Hospital Tuebingen, Tuebingen, Germany, between 2000 and 2005. All children had chronic non-infectious uveitis and received MMF for at least 6 months. All patients were given steroids or other immunosuppressive agents before initiating treatment with MMF.

RESULTS

17 children (10 boys and 7 girls) with a mean age of 8 (range 2-13) years at the onset of uveitis were examined. The average duration of follow-up after initiation of MMF was 3 (range 2-5) years. A steroid-sparing effect was achieved in 88% of the patients. The oral prednisolone was successfully discontinued in 41% children and reduced to a daily dose of < or =5 mg in 47% of the children. 24% of the patients remained relapse-free during the treatment, but a reduction in the relapse rate was observed in all other patients except one. Visual acuity was increased or maintained in 13 children (76%). Mild side effects (headache, rash, gastrointestinal discomfort) occurred in 7 patients (41%) and were the cause of discontinuation of MMF in 1 patient.

CONCLUSION

The results of our study are encouraging and suggest that MMF is an effective agent also in the treatment for uveitis in children, with marked steroid-sparing potential and an acceptable side effect profile.

Basic immunosuppressive drugs outside solid organ transplantation

Immunosuppressive drugs are the backbone of solid organ transplantation. The introduction of new immunosuppressive drugs led to improved patient and organ survival rates. Nowadays, acute rejection can be reduced to a minimum. Individualization and avoidance of drug-related adverse effects became a new goal to achieve. The potency of immunosuppressive drugs makes them attractive for use in various autoimmune diseases; therefore, the experience on immunosuppressive drugs outside the field of organ transplantation is analysed in this review.

Lupus and leg ulcers—a diagnostic quandary

Leg ulcerations can occur in systemic lupus erythematosus (SLE) patients with antiphospholipid (aPL) antibodies and/or vasculitis, and it has been suggested that aPL antibodies may play a pathogenetic role in skin manifestations of SLE. To our knowledge, there is only one report of an aPL antibody-negative patient who developed pyoderma gangrenosum (PG) several years before the diagnosis of SLE. We describe a case of a young male affected by SLE who developed leg ulcers diagnosed as PG in the absence of aPL antibodies, where the onset of PG was associated with reactivation of SLE. Effective treatment led to significant improvement in skin lesions and SLE activity.