Detection of disease change using a biological marker and clinical application: CA125 in ovarian cancer patients

In Oncology drug development, the great majority of phase 3 trials are negative.. New strategies are required to rapidly identify novel agents prior to large randomised trials. The CA125 doubling trial successfully showed that an effective drug could be identified more efficiently by testing whether the rate of increase in the tumour marker CA125 decreased after starting the novel agent, at a point identified by CA125 rising to four times it’s nadir level. However efficiency could be improved, if more patients could be included. This work explores identifying an earlier effective starting point by analysing the time course of CA125 rise.