Novelion Therapeutics Inc. announced that its subsidiary has submitted a marketing authorization application (MAA) to the European Medicines Agency (EMA) seeking approval for metreleptin as replacement therapy to treat complications of leptin deficiency in patients with congenital or acquired generalized lipodystrophy (GL) and in a subset of patients with partial lipodystrophy (PL). Metreleptin was granted orphan drug designation by the European Commission in July 2012, and if approved, carries 10 years of exclusivity in the EU. The company estimates the prevalence of GL is approximately one in one million people, and the prevalence of the subset of PL being targeted for approval is approximately one half to one in one million people. The company, through its subsidiary, will seek to market metreleptin in the EU under the tradename MYALEPTA. Generalized lipodystrophy (GL) and partial lipodystrophy (PL) are ultra-rare disorders characterized by loss of adipose tissue. Because the hormone leptin is made by fat tissue, patients with GL and PL have low levels of leptin, which regulates food intake and energy balance. Both GL and PL are associated with severe metabolic abnormalities, including hypertriglyceridemia, insulin resistance, and diabetes, which can result in life-threatening co-morbidities such as acute pancreatitis, inflammation and fatty deposits in the liver (steatohepatitis), and accelerated plaque accumulation in the arteries (atherosclerosis). Leptin is a naturally occurring hormone and an important regulator of energy homeostasis, fat and glucose metabolism. Metreleptin is an analog of leptin made through recombinant DNA technology and has been studied as a replacement therapy, in addition to diet, to treat the complications of leptin deficiency in patients with generalized or partial lipodystrophy. Open-label studies with metreleptin showed significant reductions in HbA1c (a measure of blood sugar control), fasting glucose, and triglycerides. In the U.S., metreleptin is approved under the trade name MYALEPT® for the treatment of generalized lipodystrophy, and carries a boxed warning for the risks of anti-metreleptin antibodies with neutralizing activities and lymphoma. It is available only through the MYALEPT Risk Evaluation and Mitigation Strategy (REMS) program.