Which is the Most Effective Therapy Approach for Psoriatic Arthritis?

Analysis of trial data found that etanercept monotherapy treats psoriatic arthritis as effectively as the combination of etanercept and methotrexate.

Investigators compared outcomes among 322 psoriatic arthritis patients treated with etanercept alone and another 152 patients who received both medications. Members of the 2 groups were demographically similar at baseline, though members of the monotherapy group started the trial, on average, with slightly longer disease duration than members of the combination therapy group (18.4 years vs. 17.5 years, respectively).

After 24 weeks of treatment, 80% of monotherapy patients and 83% of combination therapy patients met the Psoriatic Arthritis Response Criteria, while 70% of the patients in both groups achieved an ARC20 response, which is defined as a 20% reduction in disease burden as measured by American College of Rheumatology criteria.

Monotherapy patients were also slightly more likely — though not significantly more likely — than combination therapy patients to achieve an ACR50 response (55% vs. 48%, respectively) and an ACR70 response (35% vs. 27%, respectively).

“Little between-group difference was observed in the 28-joint Disease Activity Score with C-reactive protein, the Psoriasis Area and Severity Index, and the Health Assessment Questionnaire—Disability Index improvement,” the study authors wrote in The Journal of Rheumatology. “Further research is warranted to better understand the potential advantages and disadvantages of methotrexate use with anti-tumor necrosis factor therapy for psoriatic arthritis.”

The conclusions of the new paper echo those of several earlier studies, which have typically failed to find any benefit from treatment regimens that supplement tumor necrosis factor (TNF) inhibitors with other medications.

A 2015 study published in Rheumatic & Musculoskeletal Diseases compared outcomes in 318 combination therapy patients and 201 monotherapy patients. The overwhelming majority of combination therapy patients (91%) used methotrexate with an anti-TNF medication.

The rest (9%) used some other conventional synthetic disease-modifying anti-rheumatic drug. Combination therapy patients exhibited similar anti-TNF persistence than monotherapy patients (32 months vs. 31 months; p=0.73). They also achieved remission, on average, over a comparable period of time (21 months vs. 25 months; p=0.56).

Those findings echoed the findings of a research review that appeared 2 years earlier in Rheumatology. The authors of that review used data from 11 published articles and 3 conference abstracts.

“Most randomized controlled trials found no differences in efficacy for peripheral arthritis between patients treated with or without methotrexate. However, the studies were not powered to answer this question. Some data suggest that concomitant methotrexate may reduce the progression of structural damage. No significant differences in other outcomes have been reported,” the authors of the review wrote.

An earlier review of 21 studies that investigated some type of combination therapy in psoriatic arthritis patients did find some evidence in support of using combination therapies rather than relying on anti-TNF agents alone. That paper, which appeared 5 years ago in the Journal of Dermatological Treatment, reviewed 1 study of non-steroidal anti-inflammatory drugs and methotrexate, 3 studies of cyclosporine and methotrexate, 3 studies of non-TNF biologic inhibitors and methotrexate, and 14 studies of TNF-inhibitors and methotrexate.

The authors of that study concluded that using methotrexate in addition to biologic medication showed no ability to increase the therapeutic value of treatment but did, in some cases, appear to decrease side effects.