Morgan Stanley analyst Matthew Harrison called the long-term durability of the Soliris/Ultomiris franchise the key investor debate on Alexion, stating that current valuation implies that less than 50% of Soliris patients will switch to the next-generation version. However, the firm's survey points to a rapid switch, with physicians saying they expect 57% of their patients to switch in 6 months and 84% in the first year, Harrison tells investors. He believes robust switching, as supported by the survey data, should drive durable long-term revenue growth and he raised his price target on Alexion shares to $175 from $165 on his switch conviction. Harrison keeps an Overweight rating on Alexion.