Methotrexate use questioned for psoriatic arthritis

A new study shows that methotrexate—a systemic drug commonly prescribed as a first-line treatment for psoriatic arthritis—may not be as effective at slowing down the progression of the disease as commonly thought.

In the British study—the first large double-blind placebo study of methotrexate for psoriatic arthritis—half the participants were given methotrexate and half received a placebo. Neither the study subjects nor the researchers knew who was getting which medication. After six months, the researchers found that methotrexate had no significant effect on objective measures of the disease, such as joint inflammation or joint damage. However, some participants reported having subjective benefits, such as feeling better while taking the drug. Physicians note that this outcome of patient satisfaction should be considered as well.

Dr. Christopher Ritchlin, chief of rheumatology at University of Rochester Medical Center in New York, says that "the study examined a number of different outcomes and showed that traditional measures of joint inflammation did not improve."

Ritchlin also adds that the trial had "some deficiencies in that the maximum dose of methotrexate was 15 mg per week" and that the study took all people with psoriatic arthritis, even though the disease is highly variable. According to the National Psoriasis Foundation, mild psoriatic arthritis involves just one or two joints, while "generalized" disabling psoriatic arthritis affects three or more joints and puts patients at a higher risk for joint destruction and disability. Additionally, the number of inflamed joints in the study participants was relatively low.

"Nonetheless, based on current evidence, no controlled data supports the effectiveness of methotrexate for psoriatic arthritis, so health care providers should consider this fact when deciding on treatment strategies for psoriatic arthritis," Ritchlin said.

Sept. 20, 2012