ADC Immunogenicity Analysis

Creative Biolabs is a certified contract research organization (CRO) with GLP facility and we are experience in providing customized bioanalytical services. To support researches for therapeutic protein, especially antibody-drug conjugates (ADCs) developments, we offer a series of biochemical, immunological and radiometric based analytical services to assess the immunogenicity of an ADC in pre-clinical stages.

Immunogenicity Assessment Service

Immunogenicity refers to the development of adaptive immune responses to therapeutic biologics. Sometimes, the human immune system will recognize the therapeutic products and treat them as hostile immunogenic agents. In the case of an ADC, anti-drug antibody (ADA) is considered as one of the major immune responses against these biologics, thereby increasing the risks for adverse effect and reducing ADC efficacy. If Pharmacokinetics (PK) and Toxicokinetics (TK) studies indicate possible ADA reactions, immunogenicity assays need to be developed and performed to evaluate possible effect caused by the resulted ADAs. Moreover, assessment of the potential ADA effects on ADC is more complex than other therapeutic protein products due to the fact that all three components in an ADC (antibodies, linker or small molecules) have the potential to develop immunogenicity that result in the generation of ADAs. Creative Biolabs fully understands the complexity of ADA evaluation during ADC development. We offer a comprehensive set of immunogenicity assays, including initial screening, confirmatory screening, titer assays, and antibody neutralizing assays for ADA detection and characterization.

Flow chart of immunogenicity assays. Screening assay select all antibody respond to ADC in serum sample. The positive resulted antibodies are confirmed by confirmatory assays and followed by ADA characterization (AAPS J, 2015).

Initial Screening and Confirmatory Screening Assays

Initial screening assay is used to detect all antibodies that bind to the ADC in plasma/serum sample. It is followed by the confirmatory screening assay to identify the serum antibodies that show true positive ADC interactions. The assay threshold for distinguishing the positive and negative sample is termed “cut-point”, which refers to the level of ADA in the assays. Cut-points are calculated following statistical analysis of samples from treatment-naïve subjects. In different stages of screening assays, it is possible that more than one type of ADAs is produced during treatment and their binding affinity may vary. Therefore, there is no standard quantitative reference for ADA screening assays, making them rather qualitative measurements. Creative Biolabs provides several ADA screening assay services including radio-immuno precipitation (RIPA), electrochemiluminescence (ELC), and various plate-based ELISA analysis (bridging ELISA, sandwich ELISA…).   

Sandwich ELISA and Bridging ELISA for ADA screening assays. In bridging ELISA, ADC performs as capture agent while the ADA is detected by labeled ADC. Sandwich ELISA uses ADC coated plates to screen samples containing ADAs using labeled antispecies-specific antibodies as indicators.

Titer Assays

After screening, ADA will be further characterized by either titer or neutralizing assays. Titer assay is to semi-quantitatively determine the quantity of ADAs in titers by maximum dilution of a serum sample until it give a value above screening cut point. Titer determination assays are often performed using methods similar to screening assays except the samples are tested in sequential dilution. Depending on the method used, the cut point of titer assay can be same or different from screening assay.

Neutralizing Assay

Neutralizing assay is applied to detect serum antibodies that interfere with ADC functionalities: targeting efficiency and target interaction. Creative Biolabs provides two formats of neutralization assays to measure ADA: cell-based and non-cell based ligand binding methods. Cell-base assay is a preferred analysis, in which the presence of neutralizing antibodies with a high drug tolerance is assayed by carefully evaluated and executed steps including the selection of a drug responsive cell line, the determination of a proper endpoint readout, selection of the control neutralizing antibody, and the optimization of assay parameters. Meanwhile, given the relative simplicity and decent accuracy, non-cell based competitive ligand binding assays, in which biophysical techniques such as SPR… being extensively used, are gaining increased popularity. These assays are also available from Creative Biolabs.

Creative Biolabs adopts various assay platforms to characterize the ADC immunogenicity. Our expert scientist will help you select suitable strategies to meet the requirements of your research timeline and budget. Please contact us for more information and a detailed quote.

Reference：

1. Hock, M.; et al. Immunogenicity of antibody drug conjugates: bioanalytical methods and monitoring strategy for a novel therapeutic modality. AAPS J. 2015, 17(1): 35-43.

For Research Use Only. NOT FOR CLINICAL USE.