Assessing the Efficacy of Psoriatic Arthritis Treatments, Methotrexate & Etanercept

Etanercept monotherapy or etanercept in combination with methotrexate provides greater treatment efficacy compared with methotrexate monotherapy, according to the results of a new study presented at the 2018 ACR/ARHP Annual Meeting, October 19-24, 2018, in Chicago, Illinois.

Often prescribed for patients with psoriatic arthritis either in combination or independently, methotrexate and tumor necrosis factor inhibitors (TNFi), such as etanercept, are common medications for the autoimmune disease that also affects the skin.

Because questions on their optimal use still remain, a team of investigators evaluated the efficacy of methotrexate monotherapy relative to etanercept monotherapy and assessed the value of adding methotrexate to etanercept in key clinical domains of psoriatic arthritis, which included progressive joint damage.

Patients with active psoriatic arthritis, based on the Classification Criteria for Psoriatic Arthritis (CASPAR), were enrolled in the phase 3, randomized, controlled, double-blind, international study.

A total of 851 patients with baseline characteristics who were naïve to biologic drugs and who had no prior methotrexate use for psoriatic arthritis were randomized to 3 groups. The combination group received etanercept 50 mg plus methotrexate 20 mg (n = 283); the etanercept-mono group received etanercept 50 mg plus oral placebo (n = 284); and the methotrexate-mono group received methotrexate 20 mg plus injectable placebo (n = 284). Treatment duration was 48 weeks for all group.

The American College of Rheumatology (ACR)20 response at week 24 served as the primary endpoint and Minimal Disease Activity (MDA) response at week 24 was the key secondary endpoint. Measures of inflammatory arthritis, radiographic progression, the severity of non-articular disease manifestations, and patient-reported outcomes were additional endpoints.

Among the patients enrolled in the study, the majority were white, with a “mean (standard deviation [SD]) age of 48.4 (13.1) years, and median psoriatic arthritis duration of 0.6 years (mean [SD] 3.2 [6.3] years),” according to the study abstract.

A mean dose of >18.8 mg of methotrexate was maintained by the methotrexate-containing arms from weeks 4 to 24.

For the etanercept-mono versus methotrexate-mono groups, ACR20 and MDA response rates at week 24 were significantly greater (ACR20: 60.9% versus 50.7% [P = .29]; MDA: 35.9% versus 22.9% [P = .5]) and for the combination versus methotrexate-mono group (ACR20: 65.0% versus 50.7% [P = .005]; MDA: 35.7% versus 22.9% [P = .5]). Compared with the methotrexate-mono group, less radiographic progression was shown in the combination and etanercept-mono groups at week 48.

Aside from some differences in skin outcomes, similar results were observed in the combination and etanercept-mono groups. Adverse event rates were also similar in the 3 study groups—aside from gastrointestinal events.

From the results gathered in the first head-to-head comparison of methotrexate and TNFi that addressed fundamental questions in psoriatic arthritis treatment, study authors concluded that greater treatment efficacy was demonstrated by etanercept monotherapy or etanercept in combination with methotrexate compared to methotrexate monotherapy. Compared with etanercept treatment alone, the addition of methotrexate to etanercept did not seem to improve treatment efficacy.

Reference:

Mease PJ, Gladman DD, Collier DH, Ritchlin CT, Helliwell PS, Liu L, Kricorian GJ, Chung JB. Etanercept and Methotrexate As Monotherapy or in Combination in Patients with Psoriatic Arthritis: A Phase 3, Double-Blind, Randomized Controlled Study [abstract]. Arthritis Rheumatol. 2018; 70 (suppl 10). https://acrabstracts.org/abstract/etanercept-and-methotrexate-as-monotherapy-or-in-combination-in-patients-with-psoriatic-arthritis-a-phase-3-double-blind-randomized-controlled-study/. Accessed October 25, 2018.