One of the newest biologic agents approved for treating PsA is ustekinumab, a human monoclonal antibody (MAB) that inhibits receptor binding of cytokines interleukin (IL)-12 and IL-23. These cytokines have been identified in patients with psoriasis and PsA as further promoting inflammation. Ustekinumab recently received approval for the treatment of PsA and is given SC every 12 weeks after 2 initial doses. Further studies have also confirmed ustekinumab significantly suppressed radiographic progression of joint damage in patients with active PsA. 15 Notable AEs included infections, but there have been no cases of tuberculosis or opportunistic infections reported. 16
The most recent FDA-approved medication for PsA is apremilast. It is a phosphodiesterase-4 inhibitor, which causes the suppression of other proinflammatory mediators and cytokines active in the immune system. 10 It is given orally, uptitrating the doses over a few days until the twice-daily maintenance dosing is achieved. It is generally well tolerated with nausea and diarrhea as the most common AEs. 17 Further studies need to be conducted to assess whether this agent is able to prevent or decrease joint damage.
Other potential treatment options are currently undergoing trials to assess their efficacy and safety in treating psoriasis and/or PsA. One class targets the IL-17 cytokine pathway and includes brodalumab, a monoclonal antibody (MAB) anti-IL-17 receptor, ixekizumab and secukinumab, both MABs anti-IL-17A. Secukinumab has already received FDA approval for the treatment of plaque psoriasis (2015). Other agents currently undergoing trials are abatacept (cytotoxic T-lymphocyte antigen 4-Ig), a recombinant human fusion protein that blocks the co-stimulation of T cells9 and tofacitinib, a janus kinase inhibitor. 18 Early studies show patients achieving a response with these medications, but further long-term studies are needed. 19
Treatment Recommendations
Treatment approaches differ for patients with only psoriasis and patients with psoriasis and PsA, although some treatment modalities overlap. Recommendations for PsA have been set for each domain affected (Figure 2). The treatment approach is based on several factors, including severity or the degree of disease activity, any joint damage, and the patient’s comorbidities. Certain comorbidities are associated with PsA—cardiovascular disease, obesity, metabolic syndrome, diabetes, inflammatory bowel disease, fatty liver disease, chronic viral infections (hepatitis B or C), and kidney disease. These comorbidities can affect the choice of therapy for the patient. 20,21 Other factors affecting treatment choices include patient preference regarding mode and frequency of administration of the medication, potential AEs, requirements of laboratory monitoring or regular doctor visits, and the cost of medications. 10,22
In treating patients with psoriasis and PsA, a multidisciplinary approach is needed. Because skin manifestations of psoriasis usually develop prior to arthritis symptoms in most patients, primary care providers and dermatologists can routinely screen patients for arthritis. 10 Rheumatologists can confirm arthritis and musculoskeletal involvement, but the treatment and management of these patients will need to be in collaboration with a dermatologist. The goal of comanagement is to choose appropriate therapies that may be able to treat both the skin and musculoskeletal manifestations.
A multidisciplinary approach can also limit polypharmacy, control costs, and reduce AEs. The existence of VA combined rheumatology and dermatology clinics makes this an invaluable experience for the veteran with direct and focused patient management. In addition to controlling disease activity, the goal of treatment is to improve function and the patient’s quality of life, halting structural joint damage to prevent disability. 10 Physical and occupational therapies play an important role in PsA management as does exercise. Patients should be educated about their disease and treatment options discussed. It is also important to identify and reduce significant comorbidities, such as cardiovascular disease, to decrease mortality and improve life expectancy. 10