Fulranumab Generally Well Tolerated But Shows No Clinical Benefit for Chronic Low Back Pain

AUSTIN, TX—In a trial designed to evaluate the analgesic effects of fulranumab in patients with chronic low back pain (cLBP), the agent did not demonstrate efficacy vs. placebo but was generally well tolerated, as reported by the study authors at the American Pain Society's 30th Annual Scientific Meeting. Fulranumab, a fully human recombinant monoclonal antibody designed to neutralize the biologic actions of human nerve growth factor, which contributes to persistent pain, was not shown to be superior to placebo for moderate-to-severe cLBP.

In a study funded by Johnson & Johnson Pharmaceutical Research and Development, Raritan, NJ, Kathleen M. Kelly and colleagues reported 12-week efficacy results from the ongoing Phase 2, 104-week, multicenter, randomized, double-blind, dose-ranging, dose-loading, placebo-controlled trial evaluating the analgesic effect of several doses of adjunctive fulranumab therapy in patients with cLBP inadequately controlled with current pain therapy (eg, NSAIDs, opioids). The study included a 12-week double-blind phase (the results of which are presented here) and a 92-week double-blind extension phase. A total of 389 patients 18–80 years old with inadequately controlled moderate-to-severe cLBP were randomized to receive SQ injections every 4 weeks in one of five parallel treatment groups: placebo or fulranumab 1mg, 3mg, 3mg after a 6mg loading dose, or 10mg every 4 weeks. Of these patients, 385 (median age: 53 years; 54% women) received at least one injection of study medication (ITT population).

Study data demonstrated that fulranumab 10mg was not significantly different from placebo in change in average pain score from baseline to Week 12 (primary efficacy measure) (between-group difference in least squares mean change = -0.1 [-0.79–0.49]; P=0.65). The differences from placebo for all lower fulranumab doses were also nonsignificant (P≥0.46, unadjusted), based on a prespecified step-down, multiple comparison procedure.

Results for secondary efficacy parameters—long-term safety and tolerability—were consistent with the primary outcome. The most common adverse events (>5% total fulranumab group) during the 12-week double-blind efficacy phase for fulranumab-treated patients were diarrhea (7%), headache (7%), paraesthesia (6%), nasopharyngitis (6%), and upper respiratory tract infection (6%). Neurologic adverse events (primarily paraesthesia and hypoaesthesia) were more frequent in the fulranumab 3mg and higher dose groups (12–13%) than placebo and fulranumab 1mg groups (5%).