Application of immunoassay kits and reagents for biomarker analysis in drug development

There is a trend in pharmaceutical development to use the measurement of su rrogate or biomarkers to evaluate drug efficacy. These markers may vary fro m newly identified entities to well characterized clinical analytes such as steroids, binding proteins, peptide hormones, enzymes, etc., and ideally c an be correlated to a therapeutic endpoint. Since they are often large prot eins, immunoassays are used and we will discuss various aspects of choosing and using these methods. The simplest situation is that a manufactured kit already exists for the de sired analyte and the matrix and the application is straightforward. With i ncreasing complexity, however, the following situations may arise: purchasi ng a kit and altering it for your purpose; buying kit components from the m anufacturer and preparing an in-house assay; and developing an in-house ass ay from scratch. We will discuss examples of each. Besides providing kits or reagents, what can a kit manufacturer do to aid t he development of a drug? One item is providing information on individual c omponents of the assay such as antibody or label. Often times it is advanta geous to buy bulk reagents and prepare our own kits. Another issue is provi ding information on an assay as the customer "reverse-engineers" the kit an d tries to apply it to their own need. We have had technical representative s of one particular manufacturer contact us and ask if we were using the me thod as intended and if not, could they help with any special applications. This manufacturer now gets a lot of our business. Finally, since every pha rmaceutical company's goal is to develop successful drugs and monitoring su rrogate markers that are effective and will help in treatment, it is possib le that some assays may eventually be used in a clinical setting, and the m anufacturer could potentially profit from the marketing of this assay. We w ill discuss two specific biomarkers and how existing commercial immunoanaly tical methods were applied to their measurement.