Merck Halts Animal-Drug Sale After Cattle Walking Problem

Merck & Co. will suspend sales of its livestock-feed supplement Zilmax in the U.S. and Canada after cattle taking it had trouble walking or standing.

The sales halt is temporary while the company plans a study of the drug, Whitehouse Station, New Jersey-based Merck said today in a statement. The drugmaker, which sells veterinary and farm products in more than 140 countries, generated $3.4 billion last year from its animal health business.

Merck is taking the action after Tyson Foods Inc., the Springdale, Arkansas-based beef, poultry and pork producer, said on Aug. 8 that it was halting its use of Zilmax because of lame livestock found at its factories.

“This important step demonstrates our commitment to providing our industry partners with data that will reaffirm confidence in Zilmax,” said KJ Varma, senior vice president for global R&D of the animal-health unit. “We sincerely regret that this situation creates business challenges for our customers, but it is critical to ensure that this process is conducted appropriately and with rigorous scientific measures.”

Zilmax generated $159 million in 2012, according to Merck. The drug is given to the animals as a chemical supplement for a 20-day period to help them boost the amount of muscle weight they gain, and then stopped three days before slaughter. It’s in a class of drugs called beta agonists, which also includes Eli Lilly & Co.’s Optaflexx, sold by its Elanco unit.

Regulatory Review

Merck notified U.S. regulators about its decision to suspend sales of Zilmax, Pamela Eisele, a company spokeswoman, said in an e-mail.

The Food and Drug Administration has received “a very small number of reports of lameness or lying down in cattle treated with zilpaterol,” Shelly Burgess, an agency spokeswoman, said in an e-mail, using the chemical name for Zilmax. “FDA will review any new information to determine if there is a safety issue and, if so, will notify the drug sponsors and the public.”

Merck shares fell less than 1 percent to $47.70 at 4 p.m. New York time. The company gained 17 percent this year.

Eli Lilly hasn’t been contacted by the FDA, or had reports of any increase in cattle lameness, Colleen Parr Dekker, a spokeswoman for Lilly’s animal health unit, said in a telephone interview.

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