The FDA placed a clinical hold on a study of high-dose fasinumab, sponsored by Regeneron Pharmaceuticals and Teva Pharmaceutical Industries.

The Phase IIb study evaluating fasinumab in chronic lower back pain reported a patient with advanced osteoarthritis developing adjudicated arthropathy, or inflammation in the joints. As a result of the FDA’s decision, Regeneron completed an unplanned interim review of results and has stopped dosing in the study. Fasinumab is a monoclonal antibody designed to reduce pain sensitization. The companies announced the joint effort in September.

The study enrolled approximately 70 percent of the targeted 800 patients in four dose groups: placebo, 6 mg subcutaneously monthly, 9 mg subcutaneously monthly and 9 mg intravenously every two months. Regeneron has notified health authorities and study investigators about the decision, the company said, and patients will continue to be followed for up to 36 weeks. Regeneron and Teva are now planning to design a Phase III study of fasinumab in chronic low back pain that excludes patients with advanced osteoarthritis.