So I would like to analyse two drugs (Drug1 has no antitumor effect, Drug2 is a used chemoterapeutic agent) and whether the Drug1 can antagonize the antitumor effect of Drug2. The tests were performed and the raw data seems to confirme this idea that's why I would like to validate it with the help of the CompuSyn software.

The data we have are the followings:

cell viability values of 2 concentrations of Drug1, cell viability values of 3 concentrations of Drug 2 and of the 6 combinations. When I enter these data set (I think correctly) in CompuSyn, the CI is not presented, an NaN (not a number) is shown.

It would be great if someone could help me out or give me some suggestions.

Thank you!