Tanezumab Reduces Chronic Low Back Pain in Phase 3 Study

Topline results from a phase 3 study of tanezumab in patients with moderate to severe chronic low back pain (CLBP) indicate a statistically significant improvement in pain at 16 weeks compared to placebo.

The 10 mg dose of tanezumab met this primary endpoint, while the treatment arm receiving 5 mg of tanezumab demonstrated numerical improvement which was not statistically significant compared to placebo.

"This study demonstrates the potential of tanezumab to treat individuals suffering from moderate-to-severe chronic low back pain who have been unable to achieve relief with currently available medicines," said Ken Verburg, tanezumab development team leader, Pfizer Global Product Development, in a statement.

The study included 1832 participants who had experienced chronic lower back pain for at least 3 months. On average, participants had chronic lower back pain for 10 years.

Patients were randomized (3:2:2:2) to 4 study arms: tanezumab 5 mg every 8 weeks to week 56; tanezumab 10 mg every 8 weeks to week 56; tramadol prolonged release daily to week 56; and placebo every 8 weeks to week 16, at which point these patients were switched randomly to either tanezumab 5 mg or tanezumab 10 mg every 8 weeks to week 56. Tanezumab was delivered by subcutaneous injection and tramadol was given orally.

The primary endpoint was change in the daily average Low Back Pain Intensity (LBPI) score from baseline to week 16, which was measured on an 11-point scale.

"Many patients living with chronic low back pain suffer from constant pain, which significantly impacts their ability to perform everyday tasks," said Christi Shaw, president, Lilly Bio-Medicines, in a press release. "Lilly and Pfizer recognize the unmet needs for those living with this life-altering and debilitating condition, and continue to advance tanezumab as an innovative non-opioid treatment for these patients."

From a safety perspective, the trial showed that tanezumab was generally well tolerated over the course of 56 weeks of treatment. Participants were also observed for a 24-week safety follow-up period. The investigators observed rapidly progressive osteoarthritis (RPOA) was observed among 1.4% of patients receiving tanezumab compared to 0.1% of patients in the other treatment groups. There was a 6 to 1 ratio of RPOA type 1 to RPOA type 2 in patients receiving tanezumab.

While not observed in other treatment groups, investigators reported subchondral insufficiency fracture in 0.4% and total joint replacement in 0.7% of patients in tanezumab treatment arms. There were no events of osteonecrosis in the study.

"This is one of the longest studies conducted to date in chronic low back pain. We look forward to further analyzing these results, and believe the data from this study will support our planned future global regulatory submissions in chronic low back pain,” continued Verburg.

Tanezumab, an investigational non-opioid pain medication, is part of a class of nerve growth factor (NGF) inhibitors. It is a monoclonal antibody that targets and binds to NGF, which increase in the body following injury, inflammation, or during chronic pain. Tanezumab has not shown a risk of addiction, misuse, or dependence in studies that have been conducted.