This study was funded by Pfizer. The following authors are Pfizer employees: JC Cappelleri and A Neuhof, T Bell and C Mamolo were employees of Pfizer at the time of writing. A Forsythe, M Musat and G Tremblay are employees of Purple Squirrel Economics, which was a paid consultant to Pfizer in connection with the development of this manuscript. P Daniele was an employee of Purple Squirrel Economics at the time of writing. The authors have no other relevant affiliations or financial involvement with any organization or entity with a financial interest in or financial conflict with the subject matter or materials discussed in the manuscript apart from those disclosed. The authors wish to thank E Hubscher and C Bodin both of Purple Squirrel Economics, for manuscript writing support and for copyediting and proofreading assistance, respectively, which were funded by Pfizer.