In deciding which therapy to use, many important factors must be considered, including safety, efficacy, availability, and cost. Long-term side effects will, of course, become better known as experience with each therapy grows. In particular, biologic medications are already in their 2nd decade of use in rheumatology, but there is much less experience than with more traditional therapies. Comparisons of efficacy between therapies are hampered by the lack of quality comparative clinical trials. Clinicians are left with comparing studies which, for the most part, differ in patient population, data collection, and statistical methods. Availability of specific therapies differs depending on location: phototherapy requires ultraviolet light units and infliximab infusions require access to an infusion clinic. Availability of biologic therapies in particular is influenced by their relatively high cost and resulting difficulties with insurance coverage.
Given these limitations, we approach patients with psoriasis who require systemic therapy by performing a complete history and cutaneous examination. If there are no contraindications we generally start with NB-UVB with or without acitretin. If phototherapy is not an option due to logistical issues, methotrexate is usually started. For many patients these conventional treatments are very effective. If there is not an adequate response after approximately 12 weeks then patients may be switched to the alternative therapy or switched to a biologic medication. Occasionally PUVA is considered for patients with extremely thick plaques or patients with type V or VI skin. Cyclosporine is usually reserved for short-term treatment of flares, followed by transitioning to other therapies for long-term control.
In choosing a biologic medication, several situations may point to the use of one over another. Etanercept is the most-used biologic medication for psoriasis, in part because dermatologists have the most accumulated experience with it. In particular, biologic medications are already in their second decade of use in rheumatology, but there is still much less experience with them than with more traditional therapies in the treatment of psoriasis. Obese patients may experience better efficacy with medications dosed using weight-based calculations (efalizumab or infliximab) (Clark & Lebwohl, 2008; Strober, Gottleib, Leonardi, & Papp, 2006; Reich et al., 2006). Efalizumab also has shown efficacy in hand and foot psoriasis (Fretzin et al., 2006; Leonardi, Stofen et al., 2007). Infliximab is one of the most efficacious therapies for psoriasis and in addition works very quickly. This may be the best treatment for patients with extremely severe psoriasis and in patients where hospitalization is a consideration. Adalimumab has also shown impressive results and was approved for the treatment of psoriasis in January 2008. Prior authorization requirements may restrict its use to patients with psoriatic arthritis. Alefacept is useful in particular because a subset of patients has shown remarkable clearing of resistant psoriasis when it was given followed by narrow-band UVB therapy (Koo et al., 2006; Ortonne et al., 2005; Scheinfeld, 2005). Of note in patients who also have psoriatic arthritis, the biologics affecting TNF (etanercept, infliximab, and adalimumab) have all been FDA-approved for use in those patients.
As discussed, several longer-term trials have shown some loss of efficacy when using biologic medications, in particular etanercept and infliximab. It may then become necessary to switch those patients to a different biologic medication. There are two different options: changing to a medication in the same class (from a TNF inhibitor to another TNF inhibitor), or changing to a medication in a different class (from a TNF inhibitor to a T-cell agent such as efalizumab or alefacept). There is no strong evidence in the literature to differentiate between these two options at this time. Data exists in the rheumatologic literature showing efficacy when switching be tween TNF-inhibiting agents (Cohen et al., 2005). There is also anecdotal evidence of efficacy when switching from a TNF-inhibiting agent to a medication with a different mechanism of action or vice versa.
Dermatology Nursing. 2008;20(2):105-111. © 2008 Jannetti Publications, Inc.
All other Dermatology Nursing Editorial Board members reported no actual or potential conflict of interest in relation to this continuing nursing education article.
Cite this: Systemic Therapy for Psoriasis - Medscape - Apr 01, 2008.