Antidrug antibodies can potentially induce immune responses, especially against large-molecule drug compounds. Hence, antidrug antibodies (ADA) are heavily scrutinized by regulatory agencies. Antidrug antibody testing is a crucial component of pharmaceutical and biologics drug development. Bioanalytical laboratories such as pharmacokinetic services are increasingly offering ADA PK analysis to evaluate antidrug antibodies observed in preclinical and clinical assessments.
Antidrug antibodies can significantly influence drug efficacy, toxicology, and pharmacokinetic profile. These effects are usually due to drug-induced neutralizing antibodies against the pharmaceutical drug product. Besides, ADA analysis in clinical trials can sometimes result in unwanted reactions leading to the termination of that particular study. Hence, ADA analysis has become inevitable for biopharmaceutical drug products. The current article discusses case studies in ADA sample analysis.
Validated bioanalytical assays for antibody-drug conjugates
Regulatory bodies recommend multiple assays for characterizing immune responses against protein products with several functional domains, such as antibody-drug conjugates. Understanding potential immunogenicity is crucial while developing an antibody-drug conjugate. Regulatory agencies require assessing these immune responses to identify the impact on specific drug domain functions. These evaluations require multiple assays and domain-specific requirements, which can be complicated and require extensive method development expertise.
A robust bioanalytical laboratory with expertise in method development and validation has successfully developed a multi-tiered approach for ADA analysis. This assessment includes screening antibody-drug conjugate assay, confirmatory whole molecule antibody-drug conjugate assay, confirmatory backbone-only assay, and positive control. This approach produced a validated immunogenicity assay that can efficiently characterize immune responses against antibody-drug conjugate.
Antidrug antibody analysis for bispecific antibody therapeutics
Bispecifics are biopharmaceuticals that bind the two different epitopes. Bispecifics are of two types: IgG-like and non-IgG-like antibodies. Drug developers face numerous challenges while developing and validating immunogenicity assays for bispecific. Often, customers require ADA assays to evaluate bispecific antibody drug compounds. They provide positive controls for both bispecific arms along with mono-specific drug versions for each arm.
Scientists have utilized this information and developed and validated the bispecific antibody drug compound. Using bridging assays with acid pretreatment, scientists developed a screening and three confirmatory assays. The antidrug antibody response was evaluated for the whole drug and each mono-specific drug arm. This validated assay can successfully support sample analysis of bispecific antibody therapeutics.
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Measuring anti-vaccine antibodies
The final case study is about an antibody assay needed to detect and quantify IgGs against a vaccine. This assay is crucial for determining the reliability and efficacy of the vaccine candidate. Today, the bioanalytical community lacks guidelines and recommendations for developing vaccine antibody assays. This specific team of scientists followed a recent APPS paper recommendation to develop and validate antibody assay for measuring anti-vaccine antibodies.
This method measured anti-vaccine antibodies by titrating the samples and calculating the concentrations against a standard curve. Automation was employed to increase accuracy, precision, and sample throughput. The developed and validated assay effectively detected antibodies for multiple vaccine antigens. Hence, researchers successfully developed an antibody assay following AAPS guidelines to quantify anti-vaccine antibodies in study samples.
