The Role of Specialty Pharmacy in Boosting Psoriatic Arthritis Outcomes

Emerging therapies with unprecedented efficacy offer a promising future in the treatment of psoriatic arthritis (PsA), according to a continuing education session at the Asembia Specialty Pharmacy Summit 2017.

Presented by Pharmacy Times Continuing Education^TM, the session Supporting Specialty Pharmacies in Improving Care for Patients with Psoriasis and Psoriatic Arthritis, presented by Michael Crowe, PharmD, MBA, CSP, FMPA, senior manager of clinical services at Diplomat Specialty Pharmacy, explored optimal care for patients with PsA and the future implications of new biologic drugs for the disease.

“There are a number of new biologics coming to market for the treatment of psoriasis and psoriatic arthritis, some with novel mechanisms of action, some with efficacy we haven’t seen from the standard of care,” Crowe said. “The newest to market is a class of interleukin 17 inhibitors for psoriasis, many of which are seeking expanded indications for psoriatic arthritis. There is also the interleukin 23 inhibitor class, with outcomes in psoriatic arthritis that are very promising.”

Crowe noted during the session that psoriasis, one of the most common skin disorders worldwide, can affect nearly any part of the body. Patients may also develop scaling in painful silvery-white patches. In determining the appropriate treatment, disease severity is an important factor for providers.

Severity of disease is defined by the American Academy of Dermatology (AAD) based on the percent of body surface area (BSA) affected. Patients with psoriasis on less than 5% of their BSA have mild psoriasis, while those with greater than or equal to 5% BSA, but less than 10%, have moderate psoriasis. Having psoriasis greater than or equal to 10% BSA is considered severe.

“Treatment of psoriasis is usually a lifelong commitment; however, the specific treatment regimen may change from time to time depending on the pattern of exacerbations and remissions,” Crowe said. “The primary goal of treatment is skin normalization.”

A high proportion of patients with psoriasis may also have concomitant involvement in the joints, referred to as PsA, which is an inflammatory arthropathy associated with psoriasis, carrying symptoms such as joint pain, stiffness, and inflammation. Crowe said that anywhere from 6% to 42% of patients with psoriasis develop PsA, which can occur many years after the skin symptoms initially appear.

The severity of psoriasis and PsA, however, usually do not correlate with each other, according to Crowe. PsA can manifest with mild symptoms that are sometimes preceded by a joint injury. The course of PsA is unpredictable, and can vary from mild to severe and debilitating.

Untreated PsA can cause persistent inflammation, progressive joint damage, severe physical limitations, disability, and increased mortality. Similarly to rheumatoid arthritis, PsA can cause permanent joint damage and disability. Crowe noted that nearly one-third of patients with psoriasis are estimated to have undiagnosed PsA, which puts pharmacists in a prime position to provide counseling to patients who only have either skin or joint involvement and the potential for the other symptom developing at some point.

Treatment for PsA typically includes nonsteroidal anti-inflammatory drugs and local corticosteroid injections. However, with the current emphasis on early aggressive therapy, the AAD recommends an anti-tumor necrosis factor (TNF) agent with or without methotrexate for PsA. Crowe said the evidence also points to the need for other systemic therapies to avoid joint erosion and deforming arthritis. Specialty pharmacies can provide PsA symptom screening, appropriate therapy selection, help with drug access, set treatment expectations, handle disease exacerbations, and provide support for adherence and adverse event monitoring.

“I think psoriatic arthritis has been pertinent to specialty pharmacy since biologics were first approved in in the early 2000s,” Crowe said. “They’re growing in importance for specialty pharmacy because more biologics and more complex therapies are becoming available.”

Promising emerging therapies include guselkumab, tildrakizumab, risankizumab, and dimethyl fumarate. Future biosimilars include SB-2 (infliximab), BI-695501 (adalimumab), CHS-1420 (adalimumab), and M-923 (adalimumab).

“Additionally, data from the SPIRIT trial for ixekizumab were also promising,” Crowe said. “The primary outcome in that study was percent of patients achieving [American College of Rheumatology] ACR 20 response at 24 weeks after starting therapy, and the outcomes are looking better than any other drug we’ve seen.”

Crowe also pointed to 3 drugs that target interleukin 17, and another that targets phosphodiesterase 4, as promising novel agents that may offer new options for patients with uncontrolled PsA after treatment with TNF inhibitors.

“With such an array of varied treatment options and new ones continuing to be produced in the drug pipeline, community and specialty pharmacists can play an important role in caring for patients with psoriasis,” Crowe said. “Pharmacists can aid patients in educating them on the disease, adverse effect management, expectations of therapy, and the importance of adherence. Pharmacists also have the opportunity to monitor patients more closely, assessing for therapy efficacy and joint involvement. With such a high prevalence of psoriatic arthritis in the psoriasis population, and the difficulty and known importance of diagnosing it early, pharmacists can help identify, counsel, and triage patients with potential joint involvement sooner, leading to better outcomes.”