Development and validation of indirect and generic immunoassays to quantify free and total evolocumab in rat serum

Aim: Evolocumab is a human monoclonal antibody used in the treatment of cardiovascular diseases, which targeted proprotein convertase subtilisin kexin type 9. To accurately quantify free (including partially bound) and total evolocumab concentrations in serum, indirect and generic ELISA methods were developed and validated in rat serum. Results: Indirect ELISA was accurate and precise over the concentration range of 23.4-1500 ng/ml, and the method was validated for selectivity, specificity, accuracy and precision, dilution linearity, parallelism and stability. Similarly, generic antihuman IgG ELISA method was validated for selectivity, accuracy and precision, and dilution linearity. Moreover, incurred sample reanalysis were carried out for the above two methods, and the percent difference met the acceptable criteria. Conclusion: The validated methods can be effectively used to evaluate pharmacokinetics of free and total evolocumab after subcutaneous administration of evolocumab to rats.