TRENTON, N.J. (AP) — Drugmaker Merck & Co. is joining two dozen other pharmaceutical companies and contract laboratories in committing to not use chimpanzees for research.

The growing trend could mean roughly 1,000 chimps in the U.S. used for research or warehoused for many years in laboratory cages could be “retired” to sanctuaries by around 2020.

That’s according to Kathleen Conlee of the Humane Society of the United States, which seven years ago began urging companies to phase out all chimp research.

The trend is driven by improved technology, animal alternatives and pressure from animal rights groups, the National Institutes of Health and Congress.

Last June, reacting to an Institute of Medicine study Congress had requested that concluded nearly all chimp research is unnecessary, the NIH announced it would retire and send about 90 percent of government-owned research chimps to the Chimp Haven sanctuary in Keithville, La. It’s now home…