In October, New York–based Pfizer struck a deal with Eli Lilly of Indianapolis, to jointly develop its anti-nerve growth factor drug, tanezumab. Pfizer's painkiller, a humanized monoclonal antibody, was poised to be the first in an important new class of drugs for general pain. But in 2010, the US Food and Drug Administration (FDA) halted clinical trials of the entire drug class, including fulranumab, made by Janssen of Raritan, New Jersey, and REGN475 from Regeneron Pharmaceuticals, Tarrytown, New York, after too many participants experienced joint destruction (Nat. Biotechnol. 29, 173–174, 2011). In 2012 an advisory panel voted unanimously to allow trials to continue. “The panel was very persuasive in arguing that we have very inadequate pain treatments and that these drugs merit further study,” says Joan Bathon, director of the rheumatology division, Columbia University Medical Center in New York, and who presented to the advisory panel an independent review of trial participants who had joint replacement surgery. The panel recommended that patients be closely monitored for joint-related adverse events and that concomitant use of nonsteroidal anti-inflammatory drugs (NSAIDs) be contraindicated, as people on NSAIDs had greater joint damage. The FDA has a partial hold on tanezumab studies, pending submission of nonclinical data to the FDA, which Pfizer anticipates submitting in early 2014. Pfizer and Eli Lilly will jointly develop and commercialize tanezumab. Lilly will pay Pfizer an undisclosed amount upfront—provided the FDA gives the drug the green light. Analysts have downgraded their expectations for the novel drug. Tanezumab's market, once estimated to be about $1.2 billion will likely be worth much less. “In these patients in the study the bone was collapsing. Given the risk of joint damage, it's going to be hard to study these drugs in patients with conditions like chronic back pain or neuropathic pain,” says Bathon.