1. Department of Biostatistics, University of North Carolina, McGavran-Greenberg Hall, CB#7420, Chapel Hill, North Carolina 27599, USA
2. Seattle Genetics, 21717–30th Drive S.E., Building 3, Bothell, WA 98021, USA
3. Biogen, 300 Binney St, Cambridge, MA 02142, USA
4. Amgen Inc., One Amgen Center Drive, 24-1-B, Thousand Oaks, CA 91320, USA