Acknowledgements
We thank the patients, their families, the investigators, and site staff. We thank Sravan Karumanchi (Ann Arbor Pharmacometrics Group) for providing support for the analyses and Linh Nguyen (Exelixis, Inc.) for her contributions to initial planning for the analyses. Writing and editorial assistance was provided by Angela Cimmino, PharmD and Alexus Rivas, PharmD (Fishawack Communications, a part of Fishawack Health, Conshohocken, PA, USA), and was funded by Exelixis, Inc.