After 1,197 rheumatoid arthritis patients completed a study called MOBILITY, in which they were administered methotrexate and biweekly 200 mg doses of injectable sarilumab (Kevzara), 150 mg sarilumab doses, or placebo, they were invited to participate in an extension. In the next study, the 901 extenders (776 of whom completed the study) received 200 mg sarilumab doses and methotrexate. Although results were similar across all groups one year out, after two years, those who took 200 mg sarilumab doses throughout experienced the least disease progression.

“Overall, patients initially randomized to sarilumab 200 mg every two weeks plus methotrexate in the double-blind period had a smaller probability of radiographic progression at the end of year two than patients initially randomized to sarilumab 150 mg every two weeks plus methotrexate or placebo plus methotrexate,” write Mark Genovese, of Stanford University Medical Center, and colleagues in Rheumatology.

“Sarilumab is a monoclonal antibody that binds soluble and membrane-bound interleukin (IL)-6 receptors, and is approved for patients with moderately to severely active RA who have had an incomplete response to one or more conventional disease-modifying antirheumatic drugs,” MedPage explains.

The initial 200 mg group had a disease activity score of 2.4 (on a scale of 0 to 10), while the 150 mg and placebo groups had worse scores: 2.5. Of the 200 mg group, 62 percent saw no disease progression after the extended study, while 55 percent of the 150 mg group and 46 percent of the placebo group saw similarly promising results. The researchers found no new safety concerns.

“These data reinforce the importance of early interventions for rheumatoid arthritis,” the researchers write, although they note that a limitation is that patients who discontinued were excluded from the study. “However, this open-label extension study is ongoing, and future analyses will provide further insights into durability of response to sarilumab, including 5-year X-ray data.”