Pressure mounted on Genzyme as its shares rose 6 percent in Frankfurt a day after French drugmaker Sanofi made public its month-old proposal to buy the U.S. biotech group for $18.5 billion (11.8 billion pounds).
Sanofi Chief Executive Chris Viehbacher confirmed his proposal to pay $69 per share in cash for Genzyme on Sunday, hinting he could make a hostile takeover bid following several unsuccessful attempts to hold talks with Genzyme management.
The French group stopped short of making a direct approach to Genzyme shareholders, however, and Viehbacher sounded a conciliatory tone in an interview with Les Echos newspaper that nonetheless suggested there was a limit to his patience.
We want to show that we are determined and serious, without being threatening straightaway. Quite some time can go by yet, Viehbacher -- dubbed the Smiling Killer by some staff for his cost-cutting zeal -- he said in the interview.
Genzyme shares were up 4.3 percent at 54.71 euros ($69.60) in Frankfurt trading by 0925 GMT as investors waited for Genzyme to respond to Sanofi's proposal.
Sanofi Aventis shares were up 1.2 percent at 45.81 euros. Sanofi is due to hold a call with analysts at 1230 GMT.
Viehbacher said on Sunday that disclosing Sanofi's non-binding offer would give Genzyme shareholders a chance to see the significant shareholder value and compelling strategic fit inherent in a combination of the two companies.
Some analysts suggested Genzyme, which is trying to fix manufacturing problems that led to shortages of two of its top drugs and hit its stock price over the past year, may not get a better offer.
Sanofi realises these guys are in a corner and are thinking why should they pay over the odds?, said Navid Malik, an analyst at Matrix Corporate Capital in London.
We've not seen any white knights and if this offer doesn't go through we'll see the shares back well below $60. I don't think there is a white knight out there. I think this is the only offer Genzyme shareholders will see.
Sources previously told Reuters that Genzyme wants an offer of at least $75 per share before Sanofi could review its private financial records. Some shareholders want as much as $80 a share to clinch a deal.
However, Sanofi's top two shareholders -- cosmetics group L'Oreal and oil company Total SA -- worry that the company might pay too much for Genzyme and are not convinced it is the best fit, bankers said last week.
Genzyme stock closed on Friday at $67.62, having jumped from around $54 before news of Sanofi's interest surfaced.
Analysts have said they expect a deal to be finalised in the range of $74 to $77 a share. If Sanofi walks away, analysts see shares of Genzyme falling to the low $50-range. Some say it could take at least a year for them to rebuild the lost value.
Genzyme is the world's dominant supplier of drugs to treat Gaucher and Fabry disease -- rare, inherited disorders in which patients lack key enzymes for breaking down fats.
News of Sanofi's initial approach emerged late in July and the drugmaker sent a written expression of interest on July 29.
Sanofi said Genzyme rebuffed the offer on August 11, but after some persuasion agreed to a meeting of financial advisers on August 24.
(Additional reporting by Ben Hirschler in Stockholm)
(Reporting by Nina Sovich; Editing by James Regan and Michael Shields)