The efficacy and safety of monotherapy with fulranumab, a monoclonal antibody that neutralises human nerve growth factor (NGF), was evaluated compared with placebo and an active comparator, controlled-release (CR) oxycodone, in patients with moderate to severe chronic knee pain of primary osteoarthritis (OA).
In this phase-2, double-blind (DB), double-dummy, placebo- and active-controlled study, patients (40-80 years) were randomised (1:1:1:1) to placebo, fulranumab 3 or 9mg every 4 weeks (Q4 wk), or oxycodone CR twice-daily. Primary efficacy end-point: responder rates based on percent improvement in average osteoarthritis-related pain intensity (OAPI) scores from baseline to week-12 or when Food and Drug Administration (FDA) put a clinical hold on all anti-NGF trials, whichever was earlier. Secondary efficacy end-points: average OAPI score (week-16), Western Ontario and McMaster Osteoarthritis Index Global Score and subscales (pain, physical function, stiffness), and Patient Global Assessment.
As of an FDA clinical hold on all anti-NGF trials, only 196/300 patients were randomised and 33% (65/196) had completed 12 weeks of the 16-week DB phase. Responders were patients who did not withdraw and whose pain improved. Responder rates were not significantly different between fulranumab treatment groups (3mgQ4wk: 71%, p = 0.739; 9mgQ4wk: 80%, p = 0.843) and placebo (77%), whereas, oxycodone CR (56%) had significantly lower responder rates in comparison to both fulranumab (3mgQ4wk: p = 0.008; 9mgQ4wk: p = 0.012) and placebo (p = 0.0021). Secondary efficacy results were consistent with primary. None of the joint replacements (four in three patients) were adjudicated as rapidly progressing OA/osteonecrosis.
ClinicalTrials.gov: NCT01094262.
Low sample size because of early termination make interpretation of this study difficult, but fulranumab monotherapy resulted in significantly better pain relief and function compared with oxycodone CR (but not against placebo) and was generally well-tolerated.