Background:::PYX-106 is a novel monoclonal antibody (mAb), targeting the sialic acidbinding
immunoglobulin-like lectin 15 (Siglec-15) in the Tumor Microenvironment (TME). Precise
measurement of PYX-106 is essential for the thorough assessment of PYX-106 pharmacokinetics
in clinical investigations.
Methods:::A novel Electrochemiluminescence (ECL) immunoassay for the quantitation of PYX-
106 in human serum was developed and validated. Biotinylated anti-PYX-106 antibody Bio-A1A1
was employed as the capture antibody, and ruthenylated anti-PYX-106 antibody Ru-A3G10 was
utilized as the detection antibody in the ECL immunoassay on Meso Scale Discovery (MSD) platform.
Results:::This assay was fully validated in terms of selectivity, accuracy, precision, hook effect,
stability, etc., with a dynamic range from 50.0 to 2,500 ng/mL in human serum under the 2018
U.S. Food and Drug Administration (FDA) guidance and the 2022 U.S. FDA ICH M10 guidance.
Conclusion:::PYX-106 bioanalytical assay validation was reported for the first time in a biological
matrix, and this assay has been successfully applied to support a clinical trial PYX-106-101.