Abetimus sodium has been under development for the treatment of systemic lupus erythematosus since the early 1990s. Because its administration results in the selective reduction of circulating double-stranded DNA antibodies, La Jolla Pharmaceutical Company has focused on the agent's ability to prolong time to nephritic flare. Fourteen trials have been initiated since 1994, but the two pivotal registration trials failed to meet primary end points. The US Food and Drug Administration issued a letter in October 2004 that stated abetimus sodium was "approvable" pending the successful completion of a trial demonstrating clinical benefit. The fate of this agent lies in the ability of the company to successfully complete a phase III study.