Sanofi-Aventis makes $18.5-billion cash offer for Genzyme

Sanofi-Aventis offered to buy Genzyme Corp. for about $18.5 billion in cash, taking its bid public after the U.S. biotechnology company refused to negotiate.

The Paris-based drugmaker offered $69 a share in a letter to Genzyme Chief Executive Henri A. Termeer, repeating a proposal made July 29, Sanofi CEO Chris Viehbacher said Sunday. Sanofi is bidding for Genzyme, the world’s largest maker of medicines for genetic diseases, as products generating about 20% of its revenue face generic rivals by 2013.

Sanofi, France’s largest drugmaker, said it is making the bid public after “several unsuccessful attempts to engage Genzyme’s management in discussions.” Viehbacher said the company was prepared to “consider all alternatives” to complete an acquisition.

“If Sanofi goes hostile, I don’t believe a price under $75 will get it done,” said Mark Schoenebaum, an analyst with ISI Group. “The majority of shareholders probably will hold out until Sanofi offers something closer to $80 than $70.”

Genzyme spokesman Bo Piela declined to comment.

On Friday, Genzyme — based in Cambridge, Mass. — saw its shares rise 78 cents, or 1.2%, to $67.62 in Nasdaq trading. Sanofi shares increased 60 cents, or 1.3%, to 45.26 euros in Paris trading.