Novel pharmacological approaches in the treatment of psoriasis

Anti-inflammatory and hypolipidemic effects of the modified fatty acid tetradecylthioacetic acid in psoriasis--a pilot study

Tetradecylthioacetic acid (TTA) is a bioactive 3-thia fatty acid, giving hypolipidemic response, inhibiting the proliferation and increasing the differentiation of normal adult epidermal keratinocytes and showing anti-oxidant and anti-inflammatory effects. Psoriasis is an inflammatory disease associated with abnormalities in lipid profile, lipid peroxidation, antioxidant capacity, eicosanoid metabolism and increased frequency of cardiovascular events. On this background we have conducted a pilot study to explore the hypothesis that this modified fatty acid could improve dyslipidemia and reduce inflammation in psoriatic patients. In this double-blinded, placebo-controlled study, we assessed the metabolic effects of systemic TTA in a limited number of patients with mild to moderate psoriasis, 1000 mg TTA daily for 28 days. The most important findings were: (i) TTA reduced plasma total cholesterol, non HDL-cholesterol, LDL/HDL cholesterol ratio, triglycerides and total fatty acids; (ii) TTA decreased plasma TNF-α, IL-8 and VCAM-1; and (iii) plasma fatty acid composition changed with an increased level of monounsaturated fatty acids and decreased n-3 polyunsaturated fatty acids. In conclusion TTA exerts both hypolipidemic and anti-inflammatory effects in psoriasis patients. The results further indicate that TTA can be of therapeutic benefit for a subgroup of psoriatic patients.

[The lymphocyte: protagonism in the new era of the biological therapies]

Psoriasis is a systemic type T cell mediated immune system chronic inflammatory skin disease. These cells play an important role in the immune system and in the inflammatory response that determines the development and maintenance of the psoriasis lesions. However, greater understanding of the pathophysiology of this disease has led to the development of specific and selective biological treatments. Efalizumab is a humanized IgG1 monoclonal antibody that binds to the Leukocyte-Function-Associated Antigen 1 (LFA-1). When it binds to the CD11a--alpha subunit of LFA1--it inhibits the binding of this ligand to the intercellular adhesion molecule 1. This inhibits several processes related with the T cells that are fundamental in the pathogenesis of psoriasis: activation of the T cells in the lymph nodes, the migration of the T cells towards the dermis and epidermis and finally the reactivation of these in the inflammatory focus. The clinical studies have demonstrated that efalizumab, administered subcutaneously only once a week, provides a clinical benefit as well as improvement in the quality of life in patients with psoriasis with chronic, moderate or severe plaques. Long-term treatment studies suggest that continuous therapy with efalizumab is more beneficial in the maintenance of the improvement of the response and demonstrate that efalizumab may be administered safely for prolonged periods. Given its efficacy, rapid onset action, safety profile due to its selective action mechanism and convenience in its subcutaneous self-administration weekly, efalizumab offers a new therapeutic option, especially of interest for the treatment of psoriasis.

Pimecrolimus 1% cream in the treatment of facial psoriasis: a 16-week open-label study

BACKGROUND

Facial psoriasis requires a treatment approach other than topical corticosteroids which bear the risk of skin atrophy. Topical pimecrolimus has been shown to be effective in atopic eczema and recently in psoriasis.

OBJECTIVE

The aim of this open-label single-center investigator-initiated study was to evaluate the efficacy and safety of pimecrolimus 1% cream in patients with facial psoriasis.

METHODS

20 adults with facial psoriasis were enrolled. Pimecrolimus 1% cream was applied twice daily to psoriatic lesions of the face over an 8-week period. An 8-week follow-up was added.

RESULTS

All clinical parameters showed a significant improvement after 8 and 16 weeks compared to baseline. Pimecrolimus 1% cream was effective and well tolerated.

CONCLUSIONS

This is the first clinical study with a larger patient cohort reporting a relevant therapeutic effect and favorable safety profile of pimecrolimus 1% cream in facial psoriasis.

Exacerbation of Pityriasis Rubra Pilaris under Efalizumab Therapy

A 60-year-old woman, diagnosed as having psoriasis vulgaris in 2004 and unresponsive to standard therapies, received weekly subcutaneous injections with efalizumab. Within 9 weeks of treatment a massive aggravation of skin lesions occurred with widespread orange-tinged erythroderma, islands of normal skin on the back and the inner side of the forearms and palmoplantar hyperkeratosis. A biopsy confirmed the clinical diagnosis of pityriasis rubra pilaris. After discontinuation of efalizumab and treatment with oral corticosteroids, acitretin (30 mg/day) and PUVA therapy, the skin lesions continuously improved. Efalizumab, a fully humanized monoclonal antibody against CD11a, inhibits various T cell processes important in the pathogenesis of psoriasis. Efalizumab has been approved for the treatment of moderate to severe psoriasis, but there are no reports in the literature on the use of efalizumab for pityriasis rubra pilaris.

Disappointing results and low tolerability of photodynamic therapy with topical 5-aminolaevulinic acid in psoriasis. A randomized, double-blind phase I/II study

BACKGROUND

Based on good results in the treatment of superficial skin tumours, since the early 1990s topical photodynamic therapy with aminolaevulinic acid (ALA PDT) has been used for disseminated, inflammatory dermatoses including psoriasis. However, there is still a lack of well-documented trials.

OBJECTIVE

A prospective randomized, double-blind phase I/II intrapatient comparison study was conducted in 12 patients to investigate whether topical ALA PDT is an effective treatment for chronic plaque-type psoriasis.

METHODS

In each patient three psoriatic plaques were randomly treated with a light dose of 20 J/cm(2) and 0.1%, 1% and 5% ALA, respectively. Treatment was conducted twice a week until complete clearance or for a maximum of 12 irradiations. Therapeutic efficacy was assessed by weekly determination of the psoriasis severity index (PSI).

RESULTS

The mean percentage improvement was 37.5%, 45.6% and 51.2% in the 0.1%, 1% and 5% ALA-treated groups, respectively. Irradiation had to be interrupted several times because of severe burning and pain sensation.

CONCLUSION

Topical ALA PDT did not prove to be an appropriate treatment option for plaque-type psoriasis due to disappointing clinical efficacy, the time-consuming treatment procedure and its unfavourable adverse event profile.

Prevalence and factors associated with use of placebo control groups in randomized controlled trials in psoriasis: A cross-sectional study

BACKGROUND

The ethics and science of using placebo control groups in clinical trials have been widely debated. Few studies, however, have examined factors associated with choice of control group.

OBJECTIVE

Our aim was to assess the prevalence of use of placebo controls in randomized controlled trials in psoriasis and to identify factors associated with use of placebo controls in these trials.

METHODS

This is a cross-sectional study of randomized controlled trials in psoriasis published from January 1, 2001 to December 20, 2005 and indexed in the Cochrane Central Register of Controlled Trials. We extracted data on types of control groups used, design issues (number of patients enrolled, primary end point), disease characteristics (psoriasis type and severity), and extrascientific issues (trial location, funding source, and year of publication). We used bivariable and multivariable logistic regression to determine factors associated with use of a placebo control group.

RESULTS

Of 194 citations, 187 were available for review. One hundred thirty-five trials from 134 articles in 38 journals met inclusion criteria. Eighty-three trials (61.5%) enrolling 8171 subjects (41.7%) used active controls only, and 52 trials (38.5%) enrolling 11,406 subjects (58.3%) used placebo controls. Adjusted for trial location and funding source, trials significantly more likely to have used placebo controls included those conducted in the United States (odds ratio [OR], 5.79; 95% confidence interval [CI], 2.45-13.68; P < .001) and those funded by pharmaceutical companies (OR, 2.61; 95% CI, 1.19-5.73; P = .02). Predicted frequencies of placebo use ranged from 77.6% (industry-funded, conducted trials in the United States) to 18.6% (non-industry-funded trials not conducted in the United States).

LIMITATIONS

Our searches may not have identified all published trials, and we did not have access to data from unpublished trials.

CONCLUSIONS

Use of placebo controls has been more common in psoriasis trials conducted in the United States and funded by pharmaceutical companies. The findings suggest that ethical and scientific issues related to choice of control group in psoriasis trials are interpreted markedly differently depending on trial location and funding source.

Emerging drugs for psoriasis

Psoriasis is a chronic immune-mediated inflammatory skin disease characterised by abnormal keratinocyte differentiation and proliferation. The immunopathogenesis is complex and novel evidence shows the involvement of both innate and adaptive immune response. Type 1 T cells and their effector cytokines play a pivotal role. Several drugs under preclinical and clinical development for psoriasis are directed against the immune response, targeting activation or proliferation of T cells, their trafficking and skin-homing, or effector cytokines. Among these, great attention has been given to TNF-alpha, following the demonstration of effectiveness of anti-TNF-alpha biologicals, and to IFN-gamma inducers. Another appealing approach concerns drugs capable of inducing immunological tolerance. Progress made in the recognition of intracellular events has prompted the development of small molecules and oligonucleotides that can inhibit specific molecular targets. There is, however, a plethora of other emerging drugs, clearly suggestive of the current interest for psoriasis, which are briefly described in this paper.