Teva Pharmaceutical Industries has entered a development field abandoned by a number of big pharma companies by joining forces with Regeneron Pharmaceuticals to develop fasinumab (REGN475), an anti-NGF (nerve growth factor) antibody that is in Phase III development for osteoarthritis pain and Phase II for chronic low back pain. In December 2010, development of the entire class of NGF inhibitors was put on clinical hold by the US FDA over safety concerns related to joint destruction.