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. 2015 Sep 22;4(10):565–575. doi: 10.1002/psp4.12015

Table 2.

Generic key questions with suggested models used for addressing the questions

Type Question Analysis*
A Does data indicate a treatment effect? ECFB ∼ EBASE + COVs + Slope*Exposure +Intercept (analysis based on all data)
B Does treatment effect increase with dose? ECFB ∼ EBASE + COVs + Slope*Exposure +Intercept (data from placebo excluded)
C What are the characteristics of the E-R relationship? What is the predicted effect of dose changes? Inline graphic+Intercept, (analysis based on all data)

*ECFB indicates the change from baseline of the primary endpoint, EBASE is the baseline value of the effect variable. Exposure is an exposure variable such as the area under the concentration-time curve in a dosing interval at steady-state. COV is the contribution from covariates for the effect. Slope is the estimated slope of the E-R relationship on a linear scale. The Emax model (Type C) is parameterized by Emax, the maximal effect obtained at infinite exposure and EC50, the exposure at half-maximal effect. For any of the analysis, an intercept, representing the response at zero exposure (i.e., placebo) is included. The equations are written with ECFB as the dependent variable, assuming a continuous endpoint. Similar analyses may be applied for categorical binary endpoints, following logit transformation, and using the response rate as the dependent variable.