A Phase 3 Study of Tanezumab for Chronic Low Back Pain

This is a randomized, double blind, placebo and active controlled, multicenter, parallel group Phase 3 study of the efficacy and safety of tanezumab when administered by SC injection for up to 56 weeks in subjects with chronic low back pain. Approximately 1800 subjects will be randomized to 1 of 4 treatment groups in a 2:2:2:3 ratio (ie, 400 subjects per treatment group for the placebo, tanezumab 5 mg and tanezumab 10 mg treatment groups and 600 subjects in the tramadol PR treatment group). Treatment groups will include: 1.) Placebo administered SC at an 8 week interval plus placebo matching tramadol PR up to Week 16. At the Week 16 visit, subjects in this group who meet the efficacy responder criteria will be switched in a blinded fashion in a 1:1 ratio to either tanezumab 5 mg or tanezumab 10 mg administered SC at an 8 week interval plus placebo matching tramadol PR to Week 56; 2.)Tanezumab 5 mg SC administered at an 8 week interval plus placebo matching tramadol PR to Week 56; 3.) Tanezumab 10 mg SC administered at an 8 week interval plus placebo matching tramadol PR to Week 56; 4.) Oral tramadol PR plus placebo administered SC at an 8 week interval to Week 56. The study is designed with a total duration (post randomization) of up to 80 weeks and will consist of three periods: Screening (up to a maximum of 37 days; includes a Washout Period and an Initial Pain Assessment Period), a Double blind Treatment Period (comprised of a 16 week Primary Efficacy Phase and a 40 week Long Term Safety and Efficacy Phase), and a Follow up Period (24 weeks). The Screening Period (beginning up to 37 days prior to Randomization) includes a Washout Period (lasting 2 32 days), if required, and an Initial Pain Assessment Period (the 5 days prior to Randomization/Baseline). Prior to entering the study, subjects must have a documented history of previous inadequate treatment response to medications in 3 different categories of agents commonly used to treat and generally considered effective for the treatment of chronic low back pain.