Is there any standard on defining the drug sensitive and resistant cell lines with IC50 values?

Question

[zero_hsy]

Hello:

I am wondering how to define drug resistant and sensitive cell lines when knowing the IC50 values. I have known the lower , the more sensitive and the higher, the more resistant.

However,if I get a lot of IC50 values in one drug, how to define the sensitive and resistant? Is there any general method? Or Could you tell me some related articles to define resistant and sensitive cell lines?

Thanks a lot!