BUZZ — Arrowhead climbs on early Alzheimer's drug trial data
* Shares of drugmaker Arrowhead Pharmaceuticals rise 6.7% to $62 premarket * Co says its experimental Alzheimer's drug, ARO-MAPT, cut levels of disease-linked tau protein in spinal fluid by an average of 73% in healthy volunteers, with maximum reductions of 85%, in an early-to-mid-stage trial * Abnormal buildups of tau