Q4 Pharma Earnings Preview: Roche, Celgene, Novo Nordisk, Merck, Gilead

Roche will highlight newer drugs as cancer blockbusters feel biosimilar pressure, while Celgene will talk to investors about its pending acquisition by Bristol. Novo Nordisk has faced concerns about generic and branded competition not to mention price pressures, but its longer-term outlook is sound; Merck's Keytruda tops investors' focus; Gilead looks ahead to new CEO O'Day.