Over the last decades, the development of new drugs has allowed cancer patients to experience several lines of chemotherapy, the objective of which is a long term stabilization of the tumour. The objectives of this work was to delineate a composite index of relative antitumoural efficacy (In-RATE) of a regimen over another, including response rate (RR), median time to progression (TTP) and progression rate (PR). When considering two treatments a and b, the In-RATE was defined as RRa/RRb x TTPa/TTPb x PRb/PRa. Values significantly superior or inferior to 1 reveal an advantage for treatment a or b, respectively. The applicability of the In-RATE to published randomized trials in four frequent tumour types (colorectal, non-small cell lung, advanced ovarian and metastatic breast cancers) was suggested to more precisely distinguish the effects of different drugs, and sometimes to detect a significant difference when the published data did not conclude to statistical difference.