Antibody-drug conjugates (ADCs) and other next-generation drug modalities are unlocking new treatment possibilities. However, their unique designs can also create unexpected challenges for bioanalytical teams.
In this webinar, attendees will hear the story of a real-world ADC case study: a humanized single-chain antibody linked to a bacterial toxin protein. The team selected a bridging anti-drug antibody (ADA) assay based on the MSD platform, with the ADC biotinylated and conjugated to Sulfo-TAG, and introduced an acid dissociation step to improve drug tolerance.
Then came a surprising discovery: about 90% of naïve donor samples contained widely varying levels of pre-existing antibodies. A few low-signal samples were used to create a negative control pool, and the initial method design included screening, confirmatory, domain specificity and titer tiers.
Click below to learn how the team turned these challenges into a validated strategy for accurate ADA detection in complex clinical samples.
Because most people have been exposed to the bacterial toxin during their lifetime, it was quickly confirmed that the majority of pre-existing antibodies targeted the toxin component of the ADC. This insight directly influenced the selection of testing tiers used in the method. Changes in titer values were then used as a key indicator to determine whether treatment-boosted anti-ADC antibodies had developed over the course of treatment.
Since cut-point determination requires at least 50 samples expected to be negative, finding a sufficient number of true negative samples proved challenging. Several strategies were evaluated during method development, and one approach was ultimately selected to establish the ADA method cut-points needed for the testing cascade.
During the webinar, the featured speaker will discuss how this mitigation strategy produced reliable cut-points and strong assay sensitivity for ADA detection.
With this approach, the validated method was applied to Phase III study samples. As expected, most baseline samples were positive for pre-existing antibodies, particularly against the toxin domain. Despite this, the assay was able to identify treatment-boosted ADA and determine their domain specificity.
Register for this webinar to learn how to adapt ADA assay design to the unique bioanalytical challenges of ADCs. Topics will include practical strategies for dealing with high pre-existing antibody rates and lessons learned from real clinical sample analysis.