Alexion Pharmaceuticals, Inc., a biopharmaceutical company, and Montreal, Canada–based Enobia Pharma Corp. have signed a definitive agreement under which Alexion will acquire 100 per cent of the capital stock of Enobia, a private biopharmaceutical company focused on the development of therapies to treat patients with ultra-rare and life-threatening genetic metabolic disorders.

Enobia's lead product candidate ENB-0040 (asfotase alfa), is a human recombinant targeted alkaline phosphatase enzyme-replacement therapy for patients suffering with hypophosphatasia (HPP), an ultra-rare, life-threatening, genetic metabolic disease for which there are no approved treatment options. Alexion will acquire full worldwide development and commercial rights to asfotase alfa. Asfotase alfa was awarded orphan drug designation in the US and EU in 2008 and Fast Track status in the US in 2009, and is currently in phase II clinical development.

“Hypophosphatasia is an ultra-rare and life-threatening disease, and those patients who survive live with debilitating morbidities including skeletal deformity, severe muscle weakness, and progressive damage to vital organs,” said Leonard Bell, MD, chief executive officer of Alexion. “Asfotase alfa has shown very compelling phase II clinical data in infants and juveniles with hypophosphatasia. The acquisition of Enobia is very well aligned with Alexion's objective to develop and deliver life-transforming therapies for patients suffering with ultra-rare, severe, and life-threatening disorders.”

“Alexion has proven expertise in developing and commercializing therapies to transform the lives of patients with severe and ultra-rare disorders, making them the ideal partner to advance the work of the Enobia team and bring asfotase alfa to HPP patients around the world,” said Jonathan Silverstein, general partner of OrbiMed and Enobia chairman. OrbiMed is a controlling shareholder in Enobia.

“Enobia and our scientific collaborators have developed an elegant compound showing very promising clinical results to date,” said Dr Robert Heft, president and CEO of Enobia. “Together with Alexion, we share a sharp focus on transforming the lives of patients with severe and ultra-rare disorders. The hypophosphatasia patient community will be well served by the experience and international scope of Alexion.”

Alexion will acquire Enobia in an all-cash transaction. Under the terms of the agreement, Alexion has agreed to pay $610 million in cash upon consummation of the transaction, and up to $470 million in cash to be paid upon achievement of various regulatory and sales milestones. Alexion is not issuing equity in connection with the acquisition. The transaction is subject to customary conditions, including the expiration or termination of the waiting period under the Hart-Scott-Rodino Antitrust Improvements Act. The Boards of both companies have approved the transaction and the companies currently anticipate that the transaction will be completed in the first quarter of 2012.

Alexion intends to finance the acquisition through cash on hand and $300 million of committed bank debt.

Goldman, Sachs & Co. is acting as financial advisor to Alexion. Ropes and Gray LLP is acting as legal counsel to Alexion. Bank of America Merrill Lynch is acting as financial advisor to Enobia. WilmerHale is acting as legal advisor to Enobia.

HPP is an ultra-rare, genetic, and life-threatening metabolic disease characterized by defective bone mineralization and impaired phosphate and calcium regulation leading to progressive damage to multiple vital organs including destruction and deformity of bones, profound muscle weakness, seizures, impaired renal function, and respiratory failure.

HPP is caused by a genetic deficiency of an enzyme known as tissue non-specific alkaline phosphatase (TNSALP), which causes life-long abnormalities in metabolism of the two vital minerals calcium and phosphate, leading directly to the debilitating morbidities and premature mortality of the disease. There are currently no therapies approved for HPP.

Asfotase alfa is an investigational, highly innovative, first-in-class recombinant protein that addresses the underlying cause of HPP by targeting replacement of the missing enzyme to the necessary body tissues. Asfotase alfa is designed to normalize the genetically defective metabolic process and prevent or reverse the severe and life-threatening complications of life-long dysregulated mineral metabolism in patients with HPP.

Alexion will provide 2012 financial guidance in February, including one-time expenses related to the Enobia acquisition. 2012 non-GAAP research and development expenses are expected to transiently rise to approximately 20 to 21% of sales, due to activities associated with Enobia's programs, and then to return to the Company's target of approximately 17% to 18% of sales in 2013. Non-GAAP selling, general and administrative expenses associated with the proposed acquisition are expected to have limited impact in 2012.

Alexion is reiterating all areas of 2011 guidance provided in its third quarter 2011 earnings announcement in October.

Alexion Pharmaceuticals, Inc. is a biopharmaceutical company focused on serving patients with severe and ultra-rare disorders through the innovation, development and commercialization of life-transforming therapeutic products.