The val­ue of the CVR could not im­me­di­ate­ly be es­tab­lished.The deal is ex­pect­ed to be an­nounced by to­day, the sources said.The two com­pa­nies' boards are ex­pect­ed to vote on the agree­ment short­ly.The deal is the sec­ond-biggest in biotech his­to­ry and gives France's Sanofi, which has pur­sued Gen­zyme for near­ly nine months, a foothold in the mar­ket to treat rare dis­eases. It will help Sanofi com­pen­sate for de­clin­ing rev­enue from drugs that have lost, or are set to lose, patent pro­tec­tion.Of­fi­cials at Sanofi were not im­me­di­ate­ly avail­able for com­ment.Bo Piela, a spokesman for Cam­bridge, Mass­a­chu­setts-based Gen­zyme, said he "can­not con­firm" that an agree­ment has been reached. (Reuters)