Fasinumab (REGN475), an antibody against nerve growth factor for the treatment of pain: results from a double-blind, placebo-controlled exploratory study in osteoarthritis of the knee.

The safety, tolerability, and efficacy of fasinumab (REGN475), a fully human monoclonal antibody against nerve growth factor, was evaluated for the treatment of pain in patients with osteoarthritis (OA) of the knee. This was a 24-week, double-blind, placebo-controlled, parallel-group, repeat-dose, exploratory study. Eligible patients 40 to 75 years of age with a diagnosis of OA of the knee and moderate to severe pain were randomized 1:1:1:1 to intravenous fasinumab 0.03, 0.1, or 0.3 mg/kg or placebo and received study drug on day 1 and day 57. Pain intensity was recorded daily using the numeric rating scale. Safety and tolerability, assessed by the incidence of treatment-emergent adverse events (TEAEs), was the primary study endpoint. Secondary study endpoints included the change from baseline in daily walking knee pain and the assessment of pain, function, and stiffness using the Western Ontario and McMaster Osteoarthritis (WOMAC) index. Baseline characteristics were similar among treatment groups (N=217). After 24 weeks, the incidence of TEAEs ranged from 66.1% to 75.0% in the fasinumab groups vs. 63.6% for placebo. The most common TEAEs included arthralgia, hyperesthesia, myalgia, peripheral edema, and joint swelling. Discontinuation for TEAEs occurred in 5.6% of fasinumab patients and 3.7% of placebo patients. All 3 doses of fasinumab were associated with significant (P<.05) improvements compared with placebo in walking knee pain and WOMAC total and subscale scores. Fasinumab was generally well tolerated, and was associated with a significant reduction in walking knee pain and an improvement in function for up to 8 weeks.