[BioC] compare IC50 in DRC package

[andrea.grilli at ior.it]

Hi to all,
I have 4 cell lines, 2 in group A and 2 in group B, for which I  
calculated IC50.
I want to know if there is some difference between the 2 groups: a  
simple t-test seems to me a not correct test for this case. Do you  
know if exists in DRC package (or in any other package) a more  
specific test and how to perform it?
I checked in manual but I didn't find a solution.

Thanks in advance,
Andrea