PARIS (AP) -- Drug makers Merck & Co. and Sanofi-Aventis SA on Tuesday abandoned a year-old effort to create a veterinary medicine joint venture because of the deal's mounting complexity and regulatory hurdles.
Merck, based in Whitehouse Station, N.J., and Sanofi-Aventis say they've agreed that keeping their animal health businesses separate is in the best interests of the companies, their shareholders and their employees.
"The companies are discontinuing their agreement primarily because of the increasing complexity of implementing the proposed transaction, both in terms of the nature and extent of the anticipated divestitures and the length of time necessary for the worldwide regulatory review process," the companies said in a joint statement.
The statement by Merck and Sanofi comes a year after the companies had set out to create what they said would be the world's largest maker of pet and livestock medicines.
The combined business would have had a market share of about 29 percent. That would have put it well ahead of the current leader, Pfizer Inc.'s Fort Dodge unit, which has about 20 percent of the market.
The joint venture was to have combined Sanofi's Merial animal health business, the maker of the Frontline tick fighter, with Merck's Intervet/Schering-Plough unit. Merck bought Schering-Plough in November, 2009.
Between them, Merial and Intervet had $5.5 billion in sales in 2010.
Both Sanofi and Merck said they remained strongly committed to their animal health businesses.