VALIDATION OF IMMUNOASSAYS FOR MACROMOLECULES FROM BIOTECHNOLOGY

Guidelines have been proposed for the validation of bioanalytical meth ods applied to the support of clinical and preclinical pharmacokinetic studies. These guidelines deal primarily with accuracy, precision, se nsitivity, and establishment of the calibration curve, and are general ly applicable to quantitative immunoassays for recombinant proteins. D efinition of specificity of immunoassays for macromolecules is more di fficult than for small molecule immunoassays since the metabolism and degradation of proteins is not usually well defined and comparator ass ays are normally not available. For multifunctional molecules, however , the use of antibodies raised against the individual functional compo nents of the macromolecule for capture and detection functions in the assay can confer enhanced specificity. Immunoassays (most commonly enz yme-linked immunosorbent assays) for the detection of antibodies elici ted by treatment with macromolecules are needed to evaluate the immune response to the macromolecule when administered in vivo. The precisio n of these antibody detection assays can be characterized, whereas acc uracy is more difficult to define without a specific immunoglobulin st andard. Evaluation of the clinical significance of such antibodies mus t take into account the immunoassay results, assessment of their neutr alizing activity in in vitro tests and their effects, if any, on clini cal efficacy and safety parameters in vivo.