[Fumaric acid monoethylester: Effect on DNA-synthesis and preliminary findings in experimental studies in animals (author's transl)]

Longterm treatment of psoriasis using fumaric acid preparations can be associated with severe proximal tubular damage

Fumaric acid preparations are used as longterm and effective treatment of psoriasis. Apart from gastrointestinal, dermatological and hematological side-effects, transient renal damage was observed during treatment with fumaric acid. The case of a 38 year old woman who was treated with fumaric acid (420 mg bid) for 5 years before she complained of fatigue and weakness. According to clinical laboratory she had developed severe proximal tubular damage. Hypophosphatemia, glycosuria and proteinuria persisted although medication was stopped immediately.

Antipsoriatic effect of fumaric acid derivatives. Results of a multicenter double-blind study in 100 patients

BACKGROUND

Psoriasis vulgaris may benefit from treatment with fumaric acid and/or its derivatives; however, because different preparations have been used, results have been contradictory and difficult to interpret.

OBJECTIVE

The purpose of this clinical trial was to evaluate the therapeutic value of fumaric acid derivatives.

METHODS

A randomized double-blind study was carried out in patients with psoriasis, comparing a well-characterized formulation of fumaric acid derivatives with placebo.

RESULTS

The results indicated statistically significant superiority of the fumaric acid derivatives over placebo. Adverse events (flush, gastrointestinal disturbances) were initially relatively frequent, but decreased thereafter.

CONCLUSION

Fumaric acid derivatives were found to be effective and safe in the treatment of psoriasis.

Antiproliferative and cytotoxic profiles of antipsoriatic fumaric acid derivatives in keratinocyte cultures

Oral administration with complex mixtures of fumaric acid derivatives is known to have antipsoriatic efficacy. The present studies aimed to clarify the mode of action and toxicity of the individual compounds. Hyperproliferative HaCaT keratinocytes in monolayer cultures were exposed to fumaric acid, dimethylfumarate, zinc monoethylfumarate, calcium monoethylfumarate and magnesium monoethylfumarate at concentrations between 0.4 microM and 960 microM for 48 h. Cell proliferation was studied by [3H]thymidine incorporation. In addition 14C-labelled amino acid uptake and total protein content were measured. Direct cytotoxicity was determined by the release of cytoplasmic lactate dehydrogenase (LDH) into the culture medium. The corresponding 50% inhibition concentrations (IC50) were calculated for DNA/protein synthesis: 2.3/2.5 microM (dimethylfumarate), 133/145 microM (zinc monoethylfumarate), 215/230 microM (calcium monoethylfumarate), 275/270 microM (magnesium monoethylfumarate), > 960/> 960 microM (fumaric acid). The total protein content was less sensitive. Antiproliferative activity was found for dimethylfumarate and to a lesser degree for calcium monoethylfumarate already at the subtoxic concentrations of 1.3 and 4 microM, respectively. In the case of magnesium monoethylfumarate, zinc monoethylfumarate and fumaric acid there was no such dissociation between their cytotoxic and antiproliferative potential. These data indicate that most of the antipsoriatic potential of fumaric therapies is due to the dimethylfumarate compound.

Systemic therapy with fumaric acid derivates: new possibilities in the treatment of psoriasis

For the past two decades fumaric acid (FA) therapy has become an increasingly popular treatment in Western Europe for psoriasis. FA therapy originally was developed by Schweckendiek and subsequently standardized by Schäfer. Schäfer's fumaric acid compound therapy (FACT) consists of the oral intake of dimethylfumaric acid ester (DMFAE) and several salts of monoethylfumaric acid ester (MEFAE) in combination with topical fumaric acid therapy (1% to 3% MEFAE in an ointment or FA in bathing oils) and a diet. Schäfer claimed excellent results in a large number of patients. Preliminary studies by German dermatologists, however, revealed contradictory therapeutic results and serious side effects, and FA treatment was soon abandoned by dermatologists. To assess the value of FA therapy we conducted an open pilot study of 36 patients in which FACT therapy appeared to be rather effective. Thereafter, several controlled studies with MEFAE sodium in two different dosages versus placebo, and DMFAE versus placebo, were done. The results indicated that MEFAE sodium in dosages up to 240 mg daily was ineffective, whereas daily dosages of 720 mg resulted in a significant decrease in scaling and itching but did not affect extension of the eruption. DMFAE, 240 mg daily, produced a significant amelioration and prevented extension. Side effects of FA treatment were nausea, diarrhea, general malaise, and severe stomachache. Mild disturbances of liver and kidney function during treatment were observed with the 720 mg dosage of MEFAE and with the 240 mg dosage of DMFAE. Moreover, a relative lymphopenia with a selective decrease of suppressor T lymphocytes occurred in about 50% of the patients treated with DMFAE.(ABSTRACT TRUNCATED AT 250 WORDS)

Nephrotoxicity of fumaric acid monoethylester (FA ME)

The nephrotoxic actions of high single oral doses of fumaric acid monoethylester (FA ME) have been investigated in the rat. Fifty mg of this substance produced morphologic lesions of the glomeruli without reducing GFR. Following 100 mg, the lesions were more pronounced and GFR was diminished by about 40%. Despite of hemorrhages in kidney cortex the urines did not contain erythrocytes. Urinary protein was augmented in single cases only. Fifty to 100 mg FA ME induced a marked concentration defect after water deprivation. In parallel FA ME reduced lactate production from glucose by kidney inner medulla in vitro. After in vivo application, however, no morphologic lesions were found in this zone of the kidney. FA ME had no effect on oxygen consumption of kidney slices despite of proximal tubular lesions observed histologically after 100 mg orally. Thus, 100 mg of FA ME have distinct nephrotoxic effects in the rat.