French drugmaker Sanofi-Aventis said it has called on bid target Genzyme not to use defensive tactics to block a takeover of the U.S. biotech but to let shareholders decide on its $18.5 billion offer.

Sanofi Chief Executive Chris Viehbacher said in a letter to Genzyme CEO Henri Termeer published on Monday that the board should not stand in the way of shareholder choice if it was not prepared to enter direct talks with the French group.

"You have publicly disclosed that Genzyme's board has authorized management and the company's advisors to 'probe and evaluate alternatives' for Genzyme and its assets, including contacting third parties," Viehbacher said.

"We were encouraged to hear this, but to date, we have not been contacted or included in this process," Viehbacher added in the letter, which was dated Nov. 8. Viehbacher said certain comments made by Genzyme management seemed to be inconsistent with its publicly stated aim of maximizing shareholder returns and listening to shareholders.

Sanofi said the comments referred to three possible courses of action for Genzyme: extending the terms of some of its directors, using Massachusetts anti-takeover statutes to block a deal or adopting a "poison pill" to stop Sanofi taking control.

"We believe it would be inappropriate for the board to take these defensive actions," Viehbacher said.

"If we are unable to have a direct dialogue with you, in all fairness you should allow your shareholders the opportunity to decide for themselves whether or not to accept our proposal."
Genzyme spokesman John Lacey said the company had received the letter and was reviewing it. He declined to comment further.

Sanofi has stuck to its bid for Genzyme after the U.S. company held a series of meetings to demonstrate it was worth more than the $69 per share Sanofi has offered, citing sales of $3 billion for its experimental multiple sclerosis drug.

Genzyme executives have said their earnings forecast for next year implied a price as high as $89 per share, based on the multiple underlying Sanofi's hostile $69 per share offer. Sanofi has called $89 per share "totally unrealistic."

"This is still a game of cat and mouse. The group is putting pressure on shareholders and indirectly on the board by making this public. He who dares wins," said one analyst who asked not to be named.

Sanofi said in a statement accompanying the letter that it remained interested in working with Genzyme on a constructive basis and was committed to a mutually agreeable transaction.
"Let's be frank, what is the issue here, it's pricing," Kris Jenner, portfolio manager of the T. Rowe Price Health Sciences Fund, told the Reuters Health Summit in New York on Monday.
"It's going to be somewhere between what Sanofi wants to pay and what Genzyme wants them to pay. My sense is that anywhere between $75-$80 (per share) seems perfectly reasonable ... I think Sanofi will prevail but they will prevail at a higher price."

Genzyme officials have not been in contact with Sanofi since the French drugmaker launched its hostile bid on Oct. 4. Sanofi shares closed little changed at €51.03, while Genzyme shares closed down 0.9% at $71.06 on the Nasdaq.