dose-response curve, which precludes the use of Loewe
additivity–based models. Table 1 gives the estimated
parameters of the response surface model. The 95% lower
bound of the estimated interaction index is shown in
Figure 2, and the contour plot with log10-transformed
doses is shown in Figure 3. Strong synergistic interaction
is seen at lower doses of both antibodies. Subsequent animal
studies using the same antibodies in a xenograft
model revealed synergistic activity arising from this target
combination.14