Article of the month of September by Dr David Burke

With a recent recognition of the role of nociceptor sensitization in the pathogenesis of chronic low back pain (CLBP), drug targets having characterized that modulate hyperalgesia. With growing evidence that nerve growth factor (NGF) is a promising target in CLBP, this study assessed the effect of tanezumab a monoclonal antibody targeting NGF, for the treatment of patients with CLBP.

This randomized, double-blind, controlled study was completed at 191 sites in eight countries. Subjects were patients 18 years of age and older with axial predominant, recalcitrant CLBP of three or more months duration. All had a history of inadequate response to at least three different categories of standard care analgesics. The subjects were randomized to receive oral tramadol titrated to a maximum of 300 mg per day, tanezumab 10mg or 5mg administered subcutaneously every eight weeks or subcutaneous and oral placebos. Treatment efficacy was characterized by low back pain intensity (LBPI) and scores on the Rowland Morris Disability Questionnaire (RMDQ).

Data were completed for 1825 patients. Compared to placebo those treated with tanezumab 10mg (but not 5mg) reported significantly improved LBPI at 16 weeks (p=0.028). The proportion of patients with a 50% or greater improvement in LBPI at week 16 was 37.4% in the placebo group 43.3% in the tanezumab 5 mg group and 46.3% in the tanezumab 10 mg group (p=0.01). Those receiving tanezumab 10 mg also had greater improvement in RMDQ disability scores as compared to placebo (p=0.002). Tramadol improved low back pain intensity as compared with placebo, but only at weeks one and eight.

Conclusion: This double-blind randomized placebo controlled trial involving patients with recalcitrant chronic low back pain found that subcutaneous tanezumab 10mg significantly reduce pain and improved function after 16 weeks of treatment.
Markman, J et al. Tanezumab For Chronic Low Back Pain: A Randomized, Double-Blind, Placebo And Active Controlled Phase 3 Study Of Efficacy And Safety. Pain. 2020, September; 161 (9): 2068–2078.