Heterogeneity of PsA hinders 'sharing' RA, psoriasis therapies
SCOTTSDALE, Ariz. — Due to the diversity of its expression, psoriatic arthritis is not often able to take full advantage of treatments for similar inflammatory arthritides or psoriasis, according to a presentation here.
“Unlike rheumatoid arthritis and other inflammatory arthritides, psoriatic arthritis is very heterogeneous,” M. Elaine Husni, MD, MPH, vice chair of the department of rheumatic and immunologic diseases and director of the Arthritis Center at the Cleveland Clinic, told attendees at the Seventh Annual Basic and Clinical Immunology for the Busy Clinician symposium. “We see many different patterns and patients can shift from one pattern to another — not everyone presents with plaque psoriasis on their elbows and knees and then comes in with morning stiffness.”
Moreover, despite increased understanding of the pathophysiology of psoriatic arthritis and its connection with psoriasis, Husni noted that effective treatments for the two conditions do not always overlap.
“You would think that psoriasis and psoriatic arthritis would easily share treatments as part of the same continuum, but as we know, some drugs simply work better with the skin than the joints,” Husni said. “Similarly, we have tried to borrow a lot from rheumatoid arthritis, and now that this population is being more closely studied, we understand that we cannot just apply what we are using in rheumatoid arthritis to psoriatic arthritis.”
For example, Husni noted disparities in the use and effectiveness of combination therapy with methotrexate between rheumatoid arthritis and psoriatic arthritis.
“In rheumatoid arthritis, we understand that there are combination therapies that are doing very well, which begs the question: For psoriatic arthritis, do we keep combination therapy or do we do monotherapy?” Husni said. “I think this an area where many of us have biases from rheumatoid arthritis and assume that combination therapy is better than monotherapy.”
However, citing recent data from the SEAM-PsA trial by Philip Mease, MD, and colleagues, Husni noted that the addition of methotrexate to etanercept (Enbrel, Amgen) among patients with psoriatic arthritis provided no benefit over etanercept alone for the majority of outcomes.
“Bottom line: In the combination or etanercept monotherapy, adding methotrexate did not improve the ACR 20/50/70 score,” Husni said. “Whether this means that we should not never use methotrexate for psoriatic arthritis, it’s probably too early to say.”– by Robert Stott
Husni ME. What’s new in PsA and SpA. Presented at: Seventh Annual Basic and Clinical Immunology for the Busy Clinician; February 15-16, 2019; Scottsdale, Ariz.
Disclosure: Husni reports no relevant financial disclosures.