Drug maker Merck & Co. said it would stop using chimpanzees in its biomedical research, joining several other companies and government agencies that have phased out use of the primates in testing drugs and vaccines.

Merck, of Whitehouse Station, N.J., cited the availability of alternative methodologies that in many cases can replace the need for chimpanzees, whose close relationship to humans has raised ethical issues over their use in drug research. The company made the decision in late 2013 and disclosed it in an update on its website in January, a spokeswoman said.

The decision drew praise from The Humane Society of the U.S., an animal-protection organization that has campaigned to spare chimps from what the group says are unnecessary and painful experiments. Some drug companies including GlaxoSmithKline PLC and nonpharmaceutical companies such as Colgate-Palmolive also have ended testing in chimpanzees, according to the society.

"Merck's decision, and that of several other pharmaceutical companies, sends a strong message that private industry is moving away from chimpanzee research as the government has," said Kathleen Conlee, vice president of animal research issues for the humane society.

In 2011, the Institute of Medicine, which advises government and industry on health matters, recommended that testing in chimps be curtailed. The IOM said that while chimps' close genetic connection to humans have made them valuable for medical research, such research raised ethical issues and carried a "moral cost."

Ms. Conlee said chimps have cognitive and emotional abilities that can make them vulnerable to post-traumatic stress disorder when used in lab settings. She also said many have been warehoused as newer, alternative methodologies were developed. She estimated about 850 chimps are in labs in the U.S.

The IOM also said newer technologies have brought alternatives to using chimps, including genetically modified mice and computer simulations. Merck didn't specify which alternative methodologies it would use in lieu of chimps.

The U.S. Food and Drug Administration generally requires animal testing for proposed new drugs to measure things such as how much of a drug is absorbed into blood, but has said it supports efforts to reduce unnecessary animal testing.

The National Institutes of Health said last year it would significantly reduce the use of chimps in research and "retire" most of the chimps it owns or supports. Retired chimps were to be sent to wildlife sanctuaries.

Merck has made limited use of testing drugs in chimps, the spokeswoman said. The company did conduct hepatitis C drug testing in chimps. Merck said about 97% of its animal studies are in rodents.

Merck said it is dedicated to the ethical and responsible treatment of all animals involved in the development of medicines and vaccines.

Write to Peter Loftus at peter.loftus@wsj.com