Efficacy and safety of tanezumab versus naproxen in the treatment of chronic low back pain.

Tanezumab is a humanized monoclonal antibody that specifically inhibits nerve growth factor as a treatment for chronic pain. This phase IIB study investigated the efficacy and safety of tanezumab for chronic low back pain vs placebo and naproxen. Patients (N=1347) received intravenous tanezumab (5, 10, or 20mg every 8weeks), naproxen (500mg twice daily), or placebo. The primary efficacy end point was mean change in daily average low back pain intensity (LBPI) from baseline to week 16. Secondary end points included mean change from baseline to week 16 in the Roland Morris Disability Questionnaire and Patient's Global Assessment (PGA) of low back pain. Tanezumab 10 and 20mg had similar efficacy profiles and significantly improved LBPI, Roland Morris Disability Questionnaire, and PGA scores vs both placebo and naproxen (P⩽.05). Tanezumab 5mg provided improvement of PGA scores vs placebo (P⩽.05), and naproxen resulted in significant improvement of LBPI vs placebo (P⩽.05). Adverse event incidence was comparable across tanezumab doses but higher than with placebo or naproxen. Arthralgia, pain in extremity, headache, and paresthesia were the most commonly reported adverse events by tanezumab-treated patients. The most frequently reported adverse events resulting in discontinuation of tanezumab treatment were arthralgia and paresthesia; the highest frequency was observed with tanezumab 20mg (both 1.4%). Serious adverse event incidence was similar across treatments. In conclusion, tanezumab provided significantly greater improvement in pain, function, and global scores vs placebo and naproxen in patients with chronic low back pain.