Medical imaging is well known for its ability to produce pictures of patient anatomy for the diagnosis of disease, but perhaps more significant for drug development is its ability to produce images of physiological and physico-chemical processes in a living subject. It is the latter that gives rise to the concept of imaging biomarkers, which we may define as the subset of all bio-markers that utilize medical imaging technologies to acquire data. Medical imaging technologies include a range of modalities used in a routine clinical setting: x-ray computed tomography (CT), positron-emission tomography (PET), single-photon-emission computed tomography (SPECT), magnetic resonance imaging (MRI), ultrasound, and optical imaging.

In its 2006 Critical Path Opportunities Report, the U.S. Food and Drug Administration (FDA) defined biomarkers as "measurable characteristics that

Biomarkers in Drug Development: A Handbook of Practice, Application, and Strategy, Edited by Michael R. Bleavins, Claudio Carini, Malle Jurima-Romet, and Ramin Rahbari Copyright © 2010 John Wiley & Sons, Inc.

reflect physiological, pharmacological, or disease processes in animals or humans. Changes in biomarkers following treatments reflect the clinical response to the product. Biomarkers can reduce uncertainty by providing quantitative predictions about performance" [1]. In this chapter we will discuss imaging as a localized biomarker. Although imaging biomarkers hold great potential for accelerating drug discovery and development, in practice they are often difficult and costly to implement for specific applications, may be used inappropriately in a development setting, or may fail to provide a robust answer to the development questions being asked. We focus our discussion on understanding the opportunities for using imaging biomarkers as tools in drug development while recognizing the current challenges and how efforts to overcome these challenges are evolving.

We begin by presenting a brief overview of biological imaging. Then we discuss the general characteristics and context of an imaging biomarker along with key advantages and limitations of imaging biomarkers. We place the definition of a biomarker given above into the context of biological imaging in general and diagnostic medical imaging in particular. We follow this with an overview of the scope of imaging in drug development, highlight specific examples of established and emerging imaging biomarkers from oncology that have found utility in drug development and illustrate considerations for imaging biomarker selection. A key issue in the implementation and use of imaging biomarkers is the challenge of standardization which we then examine in some detail. We conclude by discussing current efforts to address the unique needs of imaging biomarker development.

Project Management Made Easy

Project Management Made Easy

What you need to know about… Project Management Made Easy! Project management consists of more than just a large building project and can encompass small projects as well. No matter what the size of your project, you need to have some sort of project management. How you manage your project has everything to do with its outcome.

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