Biogen Inc BIIB.O rose 2.0% after late-stage studies found its Alzheimer's drug Aduhelm significantly lowered blood levels of an abnormal form of the protein tau that accumulates in the brains of people with the disease. Wall Street's main indexes tracked weekly declines of more than 1%, their first since the turn of October, as hot U.S. inflation readings sapped investor sentiment and halted an earnings-driven streak of record closing highs. Meanwhile, Reuters reported President Joe Biden and Chinese leader Xi Jinping are expected to hold a virtual summit on Monday amid tensions over trade, human rights and military activities.