Merck ($MRK) has added its name to the growing list of entities pulling the plug on chimpanzee research, folding to activist pressure and dismissing its primate subjects once and for all. Merck was among the industry's last holdouts, according to the Humane Society, now joining GlaxoSmithKline ($GSK), Gilead Sciences ($GILD), Novo Nordisk ($NVO) and others in sparing chimps from biomedical research. The drugmaker's decision comes after the National Institutes of Health announced it would retire its more than 300 primates last year, which Director Francis Collins said was simply "the right thing to do." Story (sub. req.)