 Psoriasis is a chronic inflammatory and non-contagious skin disease. Characterized by itchy, raised, red areas of skin covered with silvery white scales, psoriasis affects 1-3 % of population worldwide, making it one of the most common skin disorders. It usually appears between the ages of 15 and 35, but can develop at any age. Apart from the physical symptoms of the disease, there can be a significant psychological and emotional impact on the lives of people with psoriasis.
People with psoriasis may feel stigmatized, causing them to avoid social interactions or activities where the appearance of their skin may attract stares or negative comments, despite the fact that psoriasis is not contagious.
At pathological level, psoriasis is marked by the abnormal growth and differentiation of a type of skin cell called keratinocyte, an inflammatory reaction and by profound alteration in the cutaneous vascular system.
It is a condition in which an individual's immune system starts reacting against their own skin cells causing the characteristic red plaques on the skin. In normal skin, cells mature in 28-30 days and are shed unnoticed. However, in psoriatic skin, the cells take only three to four days to mature and move to the surface, causing cells to pile up and form thick elevated lesions. Triggers such as psychological stress, skin trauma, medications and infections can cause worsening of symptoms or flare-ups of the disease.
The most common type of psoriasis is plaque psoriasis. The severity of chronic plaque psoriasis can be evaluated by a number of parameters including the percentage of body surface area (BSA) involved. Generally, patients with less than 10% BSA involvement are considered to have mild to moderate psoriasis, which together account for 80% of patients with chronic plaque psoriasis. Although there is no cure for psoriasis, several therapeutic options are available that help reduce the extent and severity of the disease. Those patients with the mild or moderate form of psoriasis are usually treated with topical therapies, whereas phototherapy and various systemic therapies are more commonly used for the more severe forms of the disease. However, the majority of patients are unsatisfied with current treatments.
The common, currently available topical therapies are corticosteroids, anthralin, coal tars, calcipotriene, retinoids, salicyclic acid and 5-fluorouracil. Mechanisms of actions of these drugs include anti-proliferation, immune-modulating/suppression, differentiation induction and keratolysis. Efficacies are variable, none of these treatments is target-specific and they are usually associated with significant adverse effects which prevents these drugs from being used on a long-term basis. In order to meet patient needs for the treatment of mild and moderate psoriasis, Welichem is developing a rapidly effective, safe, and readily administered topical drug, WBI-1001 cream.
Through extensive in vitro and in vivo studies in the past few years, WBI-1001 has been demonstrated to be potentially an ideal drug candidate for topical treatment of psoriasis. As a small molecule compound originally isolated from symbiotic bacterial metabolites, it can be easily synthesized and formulated as a topical treatment. The unique and fundamental characteristics are that WBI-1001 targets all major pathogenic features of the psoriatic skin including inhibiting pro-inflammatory cytokines, blocking T-cell infiltration processes, suppressing hyper-proliferative keratinocytes and T- cells, inducing normal keratinocyte differentiation, and inhibiting new blood vessel formation (angiogenesis) (figure below).
Targets of WBI-1001 in psoriatic skin.
Experimental evidence support WBI-1001 acting as a potential effective therapy by targeting the following pathogenic features of psoriasis (arrows): activated T- cells and hyperproliferative keratinocytes, angiogenesis, T cell migration and pro-inflammatory cytokines.
Welichem has completed all the preclinical toxicology tests and found no obvious side effects even with up to 30 times higher dose of that intended for human use in clinical trials. Currently, Welichem is preparing the documents for clinical trial application in Canada and it is anticipated to enter clinical trials at the end of June 2007 upon approval.
Welichem's preclinical evidences strongly indicate that WBI-1001 will be potentially a novel effective and safe treatment modality for psoriasis. In comparison with available topical treatments for psoriasis in the market, Welichem's WBI-1001 cream would have significant advantages in that:
- It targets all major pathogenic features of the disease.
- It rapidly improves the appearance of the psoriatic skin by diminishing inflammation.
- There are no obvious side effects.
- Topically applied to the skin.
Dr. Liren Tang
April 2007
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