A new industry study shows that tanezumab is an effective analgesic for osteoarthritis but confirms an increased risk of rapidly progressive OA and total joint replacement seen in earlier trials.

Tanezumab is an investigational humanised monoclonal antibody that binds and inhibits nerve growth factor. It is being developed by Pfizer and Eli Lilly and Company, which funded the current trial.

US researchers enrolled 696 patients with hip or knee OA, pain and function scores of five or greater on the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC), an inadequate response to OA analgesics and no radiographic evidence of prespecified joint safety concerns.

Patients were randomly allocated to one of three subcutaneous-injection regimens at weeks one and eight: placebo, tanezumab 2.5mg, or tanezumab 2.5mg at week one and 5mg at week eight. Intermittent paracetamol was allowed if needed.