Jefferies analyst Eun Yang downgraded TESARO to Hold citing yesterday's rally on the company's positive Phase 3 data for niraparib in ovarian cancer. The data were better than expected, but so was the stock move, Yang tells investors in a research note. The analyst prefers a Hold rating ahead of the full data set as well as competitor data in the second half of 2016 and 2017. She lists a potential takeout and competitor data not being as good as niraparib as risks to her downgrade. Yang raised her price target for TESARO shares to $75 from $53. The stock closed yesterday up $40.40, or 108%, to $77.40.