Metreleptin was approved in the United States as adjunct to diet as replacement therapy to treat the complications of leptin deficiency in patients with congenital or acquired generalized lipodystrophy in February 2014. The approval was based on results obtained in 2 open-label, investigator-sponsored studies (Studies 991265 and 20010769) conducted at the National Institutes of Health (NIH) to evaluate the safety and efficacy of metreleptin treatment in patients with lipodystrophy and 1 treatment IND (FHA101/MB002-002/MB002-002) conducted by Bristol-Myers Squibb on behalf of AstraZeneca (BMS/AZ) in patients with diabetes mellitus and/or hypertriglyceridemia related to lipodystrophy. These studies enrolled patients with lipodsytrophy including both generalized and partial lipodystrophy. Although the marketing authorization restricted the indication to patients with generalized lipodystrophy, meaningful clinical benefit was achieved in a subset of patients with partial lipodystrophy, and these patients from FHA101/MB002-002 form the basis of the request for ongoing treatment under expanded access.