A phase III study to evaluate the long-term safety and efficacy of fasinumab in patients with pain due to osteoarthritis of the knee or hip.

Background: Pain associated with osteoarthritis (OA) is frequently disabling; treatments are often ineffective or intolerable. Fasinumab selectively inhibits nerve-growth factor and has shown efficacy for the management of OA pain.

Methods: In this randomized, double-blind, phase III safety study, patients with moderate-to-severe OA pain and history of inadequate pain relief received placebo or fasinumab (at 1, 3, 6, and 9 ​mg every 4 weeks [Q4W] and 1 and 6 ​mg every 8 weeks [Q8W] for 52 weeks). Primary safety endpoints included adverse events, adjudicated arthropathies (AAs), and joint replacements (JRs). Co-primary endpoints of an efficacy sub-study were change in Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) pain and physical function scores. During the study, higher fasinumab doses were discontinued for safety; 1 ​mg doses continued.

Results: Of 13,945 patients screened, 5331 were randomized; 1074 were included in the efficacy sub-study. AAs and JRs occurred in all groups. Increased severity of disease at baseline was associated with higher rates of AAs and JRs. A dose-dependent risk of AA or JR was observed for fasinumab; in the 1 ​mg groups, only a small percentage of patients with JR had prior AA. Fasinumab significantly improved WOMAC pain and physical function scores compared with placebo; least squares mean differences versus placebo were -1.22 and ​-1.20 for 1 ​mg Q4W and -0.73 and ​-0.74 for 1 ​mg Q8W, respectively (0.001).

Conclusion: AAs and JRs showed a dose relationship to fasinumab and were associated with baseline OA status. Fasinumab achieved statistically significant improvements in WOMAC pain and physical function scores compared with placebo.