On a sunny day in San Francisco last January, AstraZeneca Chief Executive Pascal Soriot was on his way to the Westin St. Francis hotel on Union Square to give investors some unexpectedly good news. What shareholders did not know at the time was that two days earlier AstraZeneca had written to U.S. rival Pfizer rejecting its offer to buy the London-based group for close to $100 billion. Shares rose on the 2017 sales forecast as investors looked forward to a time when AstraZeneca would finally put behind it a wave of patent expiries on its drugs.