Background:
This randomized, double-blind trial assessed tanezumab in patients with Chronic Low Back Pain (CLBP) and history of inadequate response or intolerance to standard of care analgesics.

Methods:
Patients received placebo (N=409), subcutaneous tanezumab (5mg [N=407] or 10mg [N=407] every 8 weeks), or oral tramadol prolonged release (100-300mg/day; N=602). Change in Low Back Pain Intensity (LBPI) and Roland Morris Disability Questionnaire (RMDQ) scores were assessed at week 16. Safety, including joint safety, was assessed through week 80.  

Results:
Tanezumab 10mg significantly improved LBPI (primary endpoint) and RMDQ (key secondary) versus placebo at week 16 (Figure). Changes in LBPI with tanezumab 5mg were not significant versus placebo. Although mean changes in RMDQ were larger with tanezumab 5mg (-6.27) than placebo (-4.95), superiority could not concluded per the pre-defined testing strategy. Changes in LBPI and RMDQ with tramadol (mean dose=203mg/day) were not significant versus placebo. Changes in LBPI for both tanezumab groups were not significant versus tramadol. Both tanezumab groups significantly improved RMDQ compared with tramadol (unadjusted for multiplicity). Adverse event rates through 16 weeks were 46.2%, 46.9%, 51.8%, and 56.3% in the placebo, tanezumab 5mg, tanezumab 10mg, and tramadol groups, resulting in treatment discontinuation rates of 3.9%, 4.4%, 4.7%, and 8.5%, respectively.

Conclusion: 
Tanezumab 10mg significantly improved pain and function at week 16 versus placebo, while tramadol did not. The frequency of AEs and treatment discontinuations due to AEs in both tanezumab groups were lower than tramadol, but higher than placebo.

SUBCUTANEOUS TANEZUMAB VERSUS PLACEBO OR TRAMADOL IN PATIENTS WITH CHRONIC LOW BACK PAIN: 16-WEEK EFFICACY AND SAFETY RESULTS FROM A PHASE 3 STUDY