Molecular Pathology Techniques in the Preclinical Development of Therapeutic Biologics

This chapter reviews a range of molecular pathology-based techniques that are currently used in preclinical animal studies to assist in answering specific scientific questions related to target biology (expression) and biotherapeutic distribution (including off-target binding). It also highlights the importance of using a combination of appropriate complementary technologies rather than a single technique. The chapter describes an integrated approach that combines pharmacokinetics (PKs), target expression, concentration, receptor occupancy, pathology, immunogenicity, and other relevant information within the same study to characterize and interpret the absorption, distribution, metabolism, and excretion (ADME) profile of a biotherapeutic. This integrated approach can also serve to maximize the information generated in a single study and can limit the number of animals used. Methods used to determine the biodistribution of a therapeutic protein-based molecule in treated animals include wholebody autoradiography (WBA) and immunohistochemistry (IHC) using either chromagen or fluorescence-based detection methods. Keywords: ADME; biotherapeutic distribution; molecular pathology-based techniques; off-target binding; preclinical development; target expression profiling; therapeutic biologic reagent