Methotrexate – a disease-modifying antirheumatic drug – is considered a first-line treatment for psoriatic arthritis, or PsA, but a British study raises questions about whether it actually does anything to slow down the disease.

The study, published in 2012 in the journal Rheumatology, is the first large, double-blind, placebo-controlled study of methotrexate for psoriatic arthritis. This study design means half the subjects received methotrexate and half received placebo – and neither the study subjects nor the researchers knew who was getting which medication. This kind of study design is widely considered “the gold standard” because it eliminates bias.

A total of 221 PsA patients were recruited from 22 specialty rheumatology clinics in the U.K. For six months, the subjects received either methotrexate, with a target dose of 15 milligrams per week, or a placebo. Various measures of effectiveness were tallied at three and six months. These measures included the PsA response criteria, or PsARC, which looks at the number of tender and swollen joints, as well as patient and physician assessments of disease progress; the disease activity score for 28 joints, or DAS-28, which assess tenderness and swelling in 28 joints; as well as blood tests that measure inflammation. Seventy of the subjects either dropped out or were lost to follow-up.

After six months, the researchers found methotrexate had no significant effect on objective measures of disease activity. But it did seem to offer subjective benefits for some – that is, doctors and patients seemed to agree the drug was beneficial based on doctor observation and how the patients reported they felt. 

Bernard Rubin, DO, division head for rheumatology at the Henry Ford Hospital in Detroit, says that’s not an unimportant consideration. “Do many patients on methotrexate feel better? My perception is they do. There are a lot of measures of patient global well-being. If the patient feels better, that is one of your outcomes,” says Dr. Rubin, who was not involved in the study.