Development of an electrochemiluminescence assay to measure serum darbepoetin concentration in extremely preterm infants

The erythropoiesis stimulating agents (ESAs), erythropoietin (Epo) and darbepoetin (Darbe), are administered clinically to preterm infants to stimulate red cell production and decrease red blood cell transfusions. Darbe is longer acting compared to Epo, allowing for weekly administration; however, Darbe does not have a specific assay to allow for serum measurements. We developed a sensitive and specific electrochemiluminescent assay for future reliable measurement of serum and plasma Darbe concentrations in samples from preterm infants participating in the multicenter randomized Phase III Darbepoetin Trial to Improve Red Cell Mass and Neuroprotection in Preterm Infants. A multi-array electrochemiluminescence platform was used to develop an immunoassay to quantitatively measure Darbe concentrations in biological fluids. Capture and detection antibodies were identified, evaluated, and optimized. Assay sensitivity, intra- and inter-plate reproducibility, and specificity were assessed to verify the utility of the assay for the purpose of accurately measuring Darbe in these samples. A reliable and accurate assay to measure Darbe concentrations in serum or plasma was developed and validated on a clinically translatable platform. This method will be applied to quantify Darbe serum concentrations in extremely premature infants and to perform population pharmacokinetic analyses. <b>Clinical Trial Registration:</b>https://clinicaltrials.gov/study/NCT03169881. Identifier is NCT03169881.