In a clinical trial of patients with rheumatoid arthritis, treatment with a drug called upadacitinib provided greater benefits than methotrexate, the most commonly used initial therapy for rheumatoid arthritis.

Upadacitinib inhibits certain proteins called Janus kinase enzymes that are involved in inflammation. It’s approved for treating patients with rheumatoid arthritis, but only after they’ve tried methotrexate.

In the study published in Arthritis & Rheumatology, 947 patients who had not previously taken methotrexate were randomized to receive once-daily upadacitinib (15 mg or 30 mg) or weekly methotrexate for 24 weeks. Both doses of upadacitinib lessened clinical signs of arthritis and improved patient-reported symptoms to a greater extent than methotrexate. Importantly, both doses prevented further joint damage in 88% to 89% of patients, compared with 78% of patients taking methotrexate.

Treatment with the 30 mg dose provided minimal additional efficacy compared with the 15 mg dose, but it was linked with a higher rate of side effects.

“This trial convincingly demonstrates the efficacy of the JAK inhibitor upadacitinib as monotherapy in early rheumatoid arthritis. It works faster and better than methotrexate alone,” said lead author Ronald van Vollenhoven, MD, of the Amsterdam University Medical Centers, in The Netherlands. “The latter drug can be combined with corticosteroids to obtain a more rapid effect, and future studies will perhaps use that comparison.”