BioMarin Pharmaceutical Inc. announced that the European Commission has granted marketing approval for 3,4-diaminopyridine (amifampridine phosphate), for the rare autoimmune disease Lambert Eaton Myasthenic Syndrome (LEMS). Amifampridine phosphate, developed by the pharmaceutical unit (AGEPS) of the Paris Public Hospital Authority (AP-HP) and licensed from EUSA Pharma SAS, is the first approved treatment for LEMS, thereby conferring orphan drug protection and providing ten years of market exclusivity in Europe. It has also received orphan drug designation in the US.

"We are excited to bring the first approved therapeutic option to the EU to treat LEMS, a rare, serious and debilitating disease as we expand our commercial portfolio with our fourth approved product," said Jean-Jacques Bienaime, chief executive officer of BioMarin. "We are on track to launch amifampridine in the EU in mid-March and look forward to meeting with the FDA in early 2010 to determine the necessary regulatory path for this product in the US. We will also evaluate the amifampridine phosphate opportunity in a number of countries outside the US and Europe as well as the best development strategy for amifampridine in other indications."

Lambert Eaton Myasthenic Syndrome (LEMS) is a rare autoimmune disease with the primary symptoms of muscle weakness. Muscle weakness in LEMS is caused by autoantibodies to voltage gated calcium channels leading to a reduction in the amount of acetylcholine released from nerve terminals. The prevalence of LEMS is estimated at four to ten per million, or approximately 2,000 to 5,000 patients in the EU and 1,200 to 3,100 patients in the US. Approximately 50 per cent of LEMS patients diagnosed have small cell lung cancer.

Patients with LEMS typically present with fatigue, muscle pain and stiffness. The weakness is generally more marked in the proximal muscles particularly of the legs and trunk. Other problems include reduced reflexes, drooping of the eyelids, facial weakness and problems with swallowing. Patients often report a dry mouth, impotence, constipation and feelings of light headedness on standing. On occasion these problems can be life threatening when the weakness involves respiratory muscles. A diagnosis of LEMS is generally made on the basis of clinical symptoms, electromyographic testing and the presence of autoantibodies against voltage gated calcium channels.

Current treatment of LEMS can consist of strategies directed at the underlying malignancy if one is present. Unfortunately, therapy of small cell lung cancer is limited and outcomes are generally poor. Immunosuppressive agents have been tried but success is limited by toxicity, and difficulty administering the regimens. A mainstay of therapy has been 3,4-DAP but its use in practice has been limited by the drug's availability. This problem will be addressed by the introduction of BioMarin's product.

BioMarin develops and commercializes innovative biopharmaceuticals for serious diseases and medical conditions. The company's product portfolio comprises four approved products and multiple clinical and pre-clinical product candidates.