Drug Development Tools: Fit-for-Purpose Initiative Web page at http://www.fda.gov/Drugs/DevelopmentApprovalProcess/ucm505485.htm. See also Bretz F, Pinheiro SC, and Branson M. 2005. Combining Multiple Comparisons and Modeling Techniques in Dose-Response Studies. Biometrics, 61(3), 738-748. 8 21 CFR 300.50