An experimental drug might help slow early Alzheimer’s disease in a markedly different way than current treatments — by lowering the brain’s production of a protein called tau. Today two Alzheimer’s drugs can modestly slow cognitive decline by clearing away buildup of a different protein, amyloid. But tau plays a role, too, and there are no tau-targeting drugs. Researchers at the Alzheimer’s Association International Conference reported new findings Tuesday suggesting Biogen’s experimental drug diranersen also might offer that benefit. The company plans a larger study to tell. It’s one of multiple novel, but early-stage, attempts to fight the mind-robbing disease.