Fasinumab may improve pain and function in patients with hip or knee osteoarthritis (OA) who do not benefit from analgesics, according to study results published in Arthritis & Rheumatology.

The study included 421 patients with moderate to severe knee or hip OA and a history of inadequate response or intolerance to analgesics. Researchers randomly assigned patients to receive either fasinumab (1, 3, 6, or 9 mg) or placebo every 4 weeks over a period of 16 weeks; patients were followed-up to week 36. During treatment, follow-up, and active joint symptoms, the researchers used plain film radiography and magnetic resonance imaging to monitor joints.

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The study’s efficacy end points included change from baseline in week 16 in the pain and physical function subscale scores of the Western Ontario and McMaster Universities OA Index (WOMAC) and patient global assessment of OA.

Of the 421 patients, 342 completed the 36-week study period. Results indicated that compared with placebo, patients receiving all 4 doses of fasinumab had significantly greater reductions in WOMAC pain subscale scores from baseline to week 16. Mean changes were -3.5±2.1 for 1 mg, -3.4±2.4 for 3 mg, -3.1±2.3 for 6 mg, -3.8±2.5 for 9 mg, and -2.4±2.4 for placebo. Researchers observed these changes at the start of week 2, and it was maintained until week 16.

Patients receiving all 4 doses of fasinumab had reduced patient global assessment scores from baseline to 16 weeks; however, only the 1- and 9-mg doses had statistically significant differences compared with placebo (P =.0132 and P =.008, respectively).

Results indicated that 17% of patients in the fasinumab group had treatment-emergent adverse events compared with 10% in the placebo group. Among patients in the fasinumab group, 4% discontinued treatment compared with 1% in the placebo group.

A total of 25 arthropathies occurred in 7% of patients in the fasinumab group and 1% of patients in the placebo group. Researchers noted that arthropathies occurred in a dose-dependent manner, with 2 occurring among patients in the 1-mg group compared with 12 in the 9-mg group.

“The observation that the efficacy of lower doses was similar to that of higher doses but was associated with lower rates of arthropathy demands that future studies explore the benefit [vs] risk at these lower doses of fasinumab,” the researchers wrote.

Disclosure: This study was supported by Regeneron Pharmaceuticals, Inc. Please see the original reference for a full list of authors’ disclosures.

Reference

Dakin P, DiMartino SJ, Gao H, et al. The efficacy, tolerability, and joint safety of fasinumab in osteoarthritis pain: a phase IIb/III double-blind, placebo-controlled, randomized clinical trial [published online June 17, 2019]. Arthritis Rheumatol. doi:10.1002/art.41012