Online-only article: Novel therapies in psoriasis

Dr Anthony Bewley looks at the latest developments in the management of psoriasis.

Psoriasis is a largely genetic skin disease which is common, affecting approximately two per cent of the population. Patients with psoriasis often, but not always, have a family history of affected relatives. The genetics of the condition are complex, as is the phenotypic appearance of the disease (ie some patients are severely affected, even with the associated psoriatic arthropathy, while others have very limited skin disease).

Topical combination
Xamiol is a new combination preparation of betamethasone diproprionate and calcipotriol in a novel gel vehicle for scalp psoriasis.

Patients with scalp psoriasis were previously obliged to use several often quite messy topical preparations to treat their scalp disease. Xamiol is a fast acting once-daily topical gel, which is usually used overnight, facilitating patient acceptability and concordance. Improvements have been reported in two weeks.

The novel vehicle is a non-odorous, silky gel which maintains stability of both active ingredients, and which has an additional emollient action.

Xamiol is applied to the scalp via repeated parting of the hair and application of the product to the exposed scalp skin. The patient starts at one side of the head, parting and applying the preparation, and then moves to the immediately adjacent scalp and repeats the process until all the affected scalp skin has been treated. This usually takes a few minutes. The treatment is left on overnight and removed the following morning by applying shampoo a few minutes before wetting the hair in the shower or washbasin. It is best if the process is repeated on a nightly basis until the scalp psoriasis is in remission.

If there is a recurrence of the psoriasis, the gel can be applied on an as-required basis under medical supervision.

In research Xamiol has been found to be a very safe, well-tolerated and effective treatment. In addition to this it is a patient-friendly and once daily treatment that patients have found very easy to use.

Scalp psoriasis

Tacrolimus
Although tacrolimus ointment is not a new product (it has been licensed for use in atopic eczema for some years), it has been used in facial psoriasis only recently. Tacrolimus is available as a 0.1% and 0.3% ointment, but it is usually the 0.1% ointment that is used for patients with facial psoriasis.

Reports of the use of tacrolimus ointment on more widespread chronic plaque psoriasis have indicated that it is not sufficiently effective on extensor and non-facial skin. This is thought to be related to the bio-availability of the active agent.

Some have argued that once the facial psoriasis has improved with treatment, topical tacrolimus ointment may be used to prevent recurrence and flares.

The main drawback from using tacrolimus ointment is the initial erythema and burning sensation, experienced by 10-30 per cent of patients. These side-effects last for a few hours and then settle, and after three or four days of use, the erythema and burning sensation stops.

The use of topical tacrolimus in facial psoriasis is not licensed by the MHRA (this is true for very many topical and systemic preparations in dermatology) and patients should be informed of this before proceeding to use it.

Biologics
The use of biologics in the treatment of psoriasis and psoriatic arthropathy is not that new. What is new is the range and choice of biologics available for use. There are new biologic compounds in the later stages of development that are likely to be available in the next few months.

Biologics are used by secondary and tertiary care as third-line agents in the treatment of severe psoriasis who have failed to respond to conventional systemic agents or for whom other systemic treatments are inappropriate.

Severe psoriasis

Severity of psoriasis is measured by the Psoriasis Area and Severity Index (PASI), and the effect of psoriasis on the psycho-social wellbeing of the patient is measured by the Dermatology Life Quality Index (DLQI). To consider use of biologics in psoriasis, according to guidelines from NICE, a patient should usually have at least a DLQI >10 and a PASI >10.

Four biologics are approved by NICE for use in patients with psoriasis: etanercept; infliximab; efalizumab and adalimumab.

These drugs are either tumour necrosis factor alpha (TNF-α) blockers or interact with a lymphocyte ligand (CD11a).

NICE recently issued guidance about the use of adalimumab (June 2008) and infliximab (January 2008). Infliximab and efalizumab were assessed in July 2006.

A new compound, ustekinumab (an interleukin-12, IL-12, and in interleukin-23, IL-23, monoclonal antibody) has just been licensed for use in psoriasis and is due to launch in March 2009. NICE plans to issue guidance on the use of ustekinumab in September 2009.

Biologics are undoubtedly extremely beneficial for some patients with severe psoriasis who have failed on conventional therapy. There are, however, a significant number (up to one third) of patients who do not respond to biologics, and patients who are on biologics need very close supervision as side-effects such recrudescence of tuberculosis and progressive multifocal leukoencephalopathy have been recognised.

Although biologics are an increasingly important treatment for patients who have severe psoriatic disease, initiation, management and supervision of patients using these is likely to remain within specialist dermatology units.

  • Dr Bewley is consultant dermatologist at Whipps Cross University Hospital and honorary senior lecturer at Queen Mary School of Medicine, University of London.

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