Alexion to buy Synageva BioPharma in $8.4bn deal

Alexion Pharmaceuticals will buy rival Synageva BioPharma in an $8.4 billion cash-and-stock deal that will bolster Alexion's business in treatments for rare diseases, the US companies announced Wednesday.

Alexion's takeover offer is aggressive: It will pay $115 in cash and 0.6581 Alexion shares for each share of Synageva, amounting to $230 in cash and stock. That represents a 140 percent premium to Synageva's closing share price Tuesday at $95.87.

"Synageva is an ideal strategic and operational fit for Alexion that aligns with what we know well and do well -- providing life-transforming therapies to an increasing number of patients with devastating and rare diseases," said David Hallal, Alexion chief executive, in a statement.

The Alexion acquisition will add Synageva's Kanuma treatment for patients suffering from Lysosomal Acid Lipase Deficiency, a rare and life-threatening disease caused by genetic mutations that lead to a buildup of fatty material in the liver and other tissues.

Kanuma is expected to be launched on the global market this year, Hallal said. Kanuma is under a priority review for approval by US and European health authorities.

Alexion's acquisition of Synageva's treatment pipeline "creates the most robust rare disease pipeline in biotech," the companies said.

Alexion projected the combined company would achieve annual cost savings that reach at least $150 million in 2017. The transaction is expected to close in mid-2015.

Shares in Synageva shot up 112.8 percent to $204.04 in opening Nasdaq trade, while Alexion dropped 9.6 percent to $152.32.