Dyax Corp. shares jumped in the extended session Wednesday after the biotech said the U.S. Federal Trade Commission had ended the antitrust waiting period for the company's acquisition by Shire PLC . Dyax shares rallied 13% to $37.83 on heavy volume. The potential $6.5 billion deal was announced in early November, and shares of Dyax have gained more than 40% since speculation on the deal started in October. Shire is offering $37.30 a share for Dyax, along with another $4 a share with the approval of Dyax's DX-2930 hereditary angioedema treatment.
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