A Relationship Between two Fundamental Concepts in Drug Combination Theory



Theories for the dose response analysis of drug combinations have been developed along two separate lines. In the first line, mainly followed by pharmacologists, the concept of “additivity” is of central importance. A corresponding central concept in the second line, which was mainly followed by biometricians, is that of “simple similarity”. We show that simple similarity implies additivity and we give a condition under which the reverse holds.