Tuesday, March 31, 2015
New Era for Psoriasis Treatment
By: Dr. Gregory Bourgeois with Shelby Dermatology
Psoriasis is a chronic condition characterized by thick, scaly, erythematous plaques on the skin that can affect some to nearly all of the body’s surface area. Two to four percent of the general population have this disease. Psoriasis can affect more than just skin as 30 percent of patients can develop a debilitating and destructive arthritis. Also, cardiovascular risk factors, such as the metabolic syndrome and its individual components, are more prevalent in psoriasis patients compared to those without psoriasis, and there is evidence to suggest that effective treatment for psoriasis can improve the cardiovascular health in these patients.
Effective treatment for psoriasis goes beyond topical corticosteroids. Although topical corticosteroids can be the only needed treatment for mild disease, patients with over three percent of their body surface area affected, painful psoriasis lesions in sensitive locations, or with arthritic symptoms may desire more systemic treatments. Over the last 20 years, dermatologists have seen a new era come for the treatment of psoriasis.
Research has evolved from the general description that T cells were involved in causing psoriasis to the discovery of new T cell subsets that drive the disease through specific cytokine pathways. We have gone from immunosuppressing systemic medications such as methotrexate and cyclosporine to immunomodulating biologic medications. These biologic medications are typically monoclonal antibodies that block cytokines directly involved in the pathogenesis of psoriasis. They have changed our understanding of psoriasis and have brought the most effective treatments to date for this devastating disease.
The biologic landscape has undergone significant shifting over the last couple of decades through translational bench-to-bedside medical breakthroughs. The tumor necrosis factor (TNF) alpha inhibitors were the first class of biologic medications to be used for psoriasis. This class had already found indications for rheumatoid arthritis, psoriatic arthritis, and Crohn’s disease prior to their approval for moderate to severe psoriasis as TNF-α plays a role in many chronic inflammatory diseases. When given continuously, the TNF-α biologics effectively treat psoriasis, often leading to consistent PASI 75 scores in approximately two-thirds of patients treated. A PASI 75 score is defined as a 75 percent improvement from the patient’s baseline psoriasis severity index.
As research elucidated the pathogenesis of psoriasis more specifically, more targeted biologic medications that disrupted the central cytokine pathways involved in psoriasis became available. Ustekinumab, an IL-12/23 blocking antibody biologic medication, is able to lead to PASI 75 scores in up to 80 percent of patients taking the medication. Within the last few months, the IL-17 blocking antibody biologic medication secukinumab was released with data that it leads to PASI 90 scores in around 60 percent of those who take it. There are five other drugs currently in phase II trials that target IL-17 or 23.
The biologic class of medications has truly been a remarkable addition to the armamentarium of psoriasis treatments. Although they are considered immunosuppressing, their side effect profile is slim because they are tailored to specific pathways within the disease they treat. Data over many years of use have shown them to be a very safe class of medication for psoriasis patients with proper follow up with their physician. As a dermatologist, I have found it very rewarding to change someone’s life that has been riddled with embarrassing and uncomfortable psoriasis lesions for years by treating them with these medicines. The biologic medications have “changed the game” in psoriasis treatment for the good of the patient’s overall quality of life.