When there are multiple biomarkers in a therapeutic study, how do you prioritize which one to use. One possibility is to use specific criteria. The easiest one of them is to select one that gives you the best signal/noise. A strong signal for your efficacy marker will enable you to detect small changes in the efficacy for your therapeutic. That biomarker needs to be specific and targeted.
Multiple biomarkers are selected because they may select various aspects. For example, a target engagement biomarker will show how the drug is engaged but does not show efficacy. On the other hand, a functional biomarker may show the effect of the drug on physiological measure and provides supportive evidence that the effect of the drug is not just a biomarker that is changed without any functional effect.
There are many other aspects – such as signal to noise, feasibility and others but it is very hard to generalize rules and depends on specific use cases.
