Non-opioid pain drug tanezumab from Pfizer and Eli Lilly improved lower back pain better than a placebo in a phase III study.

 Tanezumab from Pfizer and Eli Lilly is a monoclonal antibody that acts as a nerve growth factor (NGF) inhibitor. It is being investigated as a non-opioid treatment for pain. This class of drugs has presented some safety concerns and in 2010 and 2012, the U.S. Food and Drug Administration (FDA) placed clinical holds on them. The agency lifted a hold placed on tanezumab in 2015, allowing Pfizer and Lilly to move forward with a late-stage study, and the results are just now being reported.

The trial revealed that a lower dose (5 mg) of tanezumab, while providing numerically better results than a placebo, did not provide statistically significant improvement. A dose of 10 mg of tanezumab, however, did perform better than the placebo at treating moderate-to-severe chronic low back pain after 16 weeks. The 10-mg dose arm succeeded in delivering a statistically significant result.

With regard to safety concerns, the companies report that tanezumab was well tolerated, although rapidly progressive osteoarthritis was seen in 1.4% of tanezumab patients (either dose) compared with 0.1% in other treatment groups. Most of the patients with rapidly progressive osteoarthritis experienced accelerated joint space narrowing, not damage and deterioration of the joint. There were also no reports of osteonecrosis in the study.

.Since tanezumab is the first NGF inhibitor to reach this late a development stage, how well it navigates the regulatory approval pathway could impact others that follow, such as fasinumab, which is being developed by Regeneron and Teva.

Pfizer and Lilly previously performed phase III studies of tanezumab as a treatment for osteoarthritis pain, both of which largely met efficacy endpoints and had incidence rates of rapid progressive osteoarthritis in 2.1% and 1.3% of the treatment arms. The companies have two additional phase III trials focused on osteoarthritis pain and chronic low back pain to report on in 2019.