Sard Verbinnen & Co. is handling media for Alexion's $8.4B bid announced today for Synageva BioPharma Corp., the Lexington, MA, maker of treatments for rare diseases.

The cash/stock deal is valued at twice the market cap of Synageva.

The Wall Street Journal notes the big premium is due to the "relatively higher prices" charged for rare disease treatments that go to smaller patient populations.

Synageva plans a global launch of Kanuma, which treats LAL Deficiency that causes a build-up of fatty material in the liver, spleen, gut and walls of blood vessels.

The company also produces enzymes to target Hunter syndrome, Farby disease and Pompe disease.

Alexion, which is based in Cheshire, Conn., produces a treatment for a deadly metabolic disorder. It said the Snyageva acquisition will expand manufacturing capability and generate cost savings of at least $150M in 2017.

David Hallal has helmed Alexion since April when he replaced company founder Leonard Bell.

Sard Verbinnen's Andrew Cole and Devin Broda Alexion work the Alexion account.