KCAS Webinar (Dec 18th) – Navigating the Bioanalytical Complications of ADCs: Applying the Appropriate Technologies

 

 

 

As the field of oncology has evolved, the toxicity of therapeutic agents has driven the development of drugs that target and kill tumors compared to more general therapies that can also impact healthy cells. Principal amongst these therapies is the use of antibody-drug conjugates (ADCs) that are typically composed of an antibody attached to a cytotoxic agent via a chemical linker. Analysis of ADCs presents a number of PK & ADA bioanalytical GLP validation challenges where the different parts of the complex are better addressed by different technologies (LC/MS, Hybrid LC/MS & LBA).

 

The bioanalytical strategy also depends on what answers you are looking for from your quantitative data. In most cases, the strategy would be to use ligand binding assays to address questions regarding the ADC complex or the antibody used in administration. For measurements of the small molecule cytotoxic agent LC-MS/MS would be the technology of choice. This seminar will focus on a number of case studies and KCAS’ application of optimal technologies to get the best possible data to support ADC drug development studies.

 

Example analytical needs include…

Conjugated payload – How much payload is attached to the antibody?

Free payload – Is any payload released from the ADC prior to reaching the site of action?

Total payload – How much free and conjugated payload is present?

Conjugated antibody – How much antibody is present with payload attached?

Total antibody – How much conjugated & unconjugated antibody is present?

Is there significant rate of immunogenicity?

In most cases, the strategy would be to use ligand binding assays to address questions regarding the ADC complex or the antibody used in administration. For measurements of the small molecule cytotoxic agent LC-MS/MS would be the technology of choice.

The small molecule payload in approved ADCs have typically included a variety of compound classes including calicheamicins, auristans (MMAE, MMAF etc) and mertansine. As the field has matured, the range of payloads has expanded to include active metabolite and peptide moieties. The concentrations in conjugated payload or total measurements can be relatively high so simple sample clean-up procedures such as protein precipitation are sufficient prior to introduction the LC system. Acid hydrolysis is used to cleave the payload from the antibody to facilitate these assays.

 

If the ADC works as it should free payload concentrations should be much lower indicating that the small molecule has been delivered to the intended site of action. The high sensitivity requirements of a free assay will likely necessitate the use of more rigorous cleanup techniques to isolate the analyte as well as a higher sensitivity mass spectrometer.

 

Mass spectrometry can be very helpful if there are issues, such as selectivity, with ligand binding strategies for the antibody portion. Measurement of the antibody will follow the strategy of monitoring one or more specific peptides following digestion with trypsin or another enzyme. This brings the analyte of interest into the mass range of the mass spectrometer. Sensitivity requirements can be met using immunoaffinity based extraction with additional on-line affinity capture should additional selectivity be needed.

 

This seminar will focus on a number of case studies and KCAS’ application of optimal technologies to get the best possible data to support ADC drug development studies.

 

KCAS has integrated, on-site research divisions that can work together and streamline the complexities of ADC analyses to deliver reliable, defendable data on time. We have the scientific expertise and equipment to develop and validate both the LC-MS/MS based methods as well as the LBA based methods to successfully support your ADC program.

If you have any questions about this or any other services from KCAS, we invite you to reach out using the form below!