In April, the IMS Institute released a new report that U.S. drug spending in 2014 rose 13.1 percent to $373.9 billion, the largest single year increase in spending since 2001. A number of factors drove the increase including the launch of innovative new therapies such as Gilead’s hepatitis C drug Sovaldi. We spoke to Murray Aitken, executive director of IMS Institute for Healthcare Informatics, about the new report, the confluence of factors that drove spending higher, and what the outlook is for 2015 and beyond.