INTRODUCTION TO BIOMARKERS - Flow Cytometry in Drug Discovery and Development - page 52

INTRODUCTION TO BIOMARKERS

O LE V ESTERQVIST AND M ANJULA P. R EDDY

3.1 INTRODUCTION

The use of biological markers (biomarkers) in diagnosing human diseases is by no
means novel. Many biomarkers such as blood pressure, cholesterol, and glucose levels
in blood are well established in the scientific community, whereas others have not yet
been “accepted” as diagnostic or prognostic biomarkers. The continuous discovery of
new biomarkers and the development of new technologies to measure biomarkers
have provided us with a plethora of tools to characterize the effects of drugs. We have
also seen new biomarkers making their way not only to clinical diagnostics, but also
to clinical prognostics and theranostics where biomarkers are used to predict the
likelihood of disease progression irrespective of interventional therapy and to predict
the response of a patient to a specific therapeutic. Many biomarkers are used in both
preclinical and clinical studies facilitating an improved understanding of the differ-
ence between mechanism of action of the drug in humans and various animal models
used in discovery. This has also allowed us to break down the “wall” between
discovery and clinical development, creating a space for translational medicine and
biomarkers [1].
Biomarkers have over the past decade become an important part of decision
making in both discovery and clinical drug development, especially in the early
phases of clinical development as part of a strategy to demonstrate “proof of concept”.
Health authorities are increasingly expecting drug companies, particularly in oncol-
ogy, to demonstrate identification of clinical benefits in a subset of patients with
particular characteristics as opposed to a one-size-fits-all approach of treatment in
light of low response rates of most of the current oncology drugs in the market.