Cutting Edge Treatments in Psoriatic Arthritis

Category: Inflammatory Spondyarthropathy Published on Monday, 12 May 2014 Written by Yong Tsai, MD

Do you have itchy, scaly skin on your elbows, knees, scalp, navel or ears? Do your fingernails and toenails sometimes lift up? Do your joints and surrounding tendons swell? Do your fingers resemble little sausages? Well, you just might have psoriatic arthritis.

Psoriasis and psoriatic arthritis are chronic inflammatory and autoimmune disease, which occurs when our immune system mistakes our own skin and joint tissue for a foreign invader, attacking it and causing inflammation. When the inflammatory process advances, chemical mediators released from white blood cells damage skin, cartilage, bone, and ligaments causing joints to become deformed.

Psoriasis is characterized by a scaly, itchy skin rash, often on the elbows, knees, scalp, behind the ears, or on the navel. Furthermore, about ten percent of those who suffer with psoriasis will develop psoriatic arthritis (PsA).  Usually, if you have psoriatic arthritis, you would develop psoriasis in your late teens, followed by arthritis in your thirties or forties. However, some patients do develop arthritic symptoms prior to psoriasis and some patients develop both at the same time.  About 95% of people with psoriatic arthritis experience swelling of the hand, wrist, elbow, knee, ankle, foot joints, and their surrounding tendons. Such swelling gives fingers and toes a sausage-like appearance, which makes grasping an object or making a fist very painful. 

Over the years, studies have demonstrated that disease-modified anti-rheumatic drugs (DMARDs) such as methotrexate, leflunomide and sulfasalazine are effective in treating PsA.  In the past decade, due to breakthroughs in genetic engineering and a better understanding of chemical mediators in inflammation, tumor necrosis factor-alpha (TNF-alpha), and Interleukin-12, interleukin 23, have proven to be the key chemical mediators, which initiate, maintain and perpetuate inflammation and cause joint damage. Therefore, blocking these key chemical mediators can impede and even prevent joint pain and damage. 

Five anti-TNF biologics, which have been approved by FDA for treatment of PsA, are Enbrel, Humira, Remicade, Cimza and Simponi which block chemical action of TNF.  Stelara, another kind of biologics, targets IL-12/ IL-23 cytokines and makes them unavailable for use in the inflammatory process. As a result, these drugs impede the inflammatory response, ease joint pain and swelling, and effectively slow down bone and cartilage damage.  In March, 2014, The FDA approved Otezla to treat adults with active psoriatic arthritis (PsA). Otezla inhibits an enzyme called phosphodiesterase 4 (PDE4), to suppress inflammation in people with PsA and help control symptoms of the disease.

Due to the safety issues and cost, not all patients with PsA need to be treated with biologics.  Most patients with PsA can be treated effectively with conventional DMARDs.  Biologics should be used in a highly selective way for patients who would benefit from cutting edge treatment.

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