Laura Moriarty
Significant progress has been made in understanding diseases, such as cancer, resulting in the development of new antibody-based therapies, including antibody-drug conjugates and bispecific monoclonal antibodies. However, these innovative therapies present challenges at the development and manufacturing stages. Fortunately, new technological advances are making it easier for scientists to identify highly specific antibodies for therapeutic use and to monitor efficacy and toxicity throughout the development and manufacturing process.
Improved understanding of biological processes and the diseases which affect them has enabled the development of novel biotherapeutic drugs, such as antibody-mediated therapies. Antibody-mediated therapies are of particular interest as cancer treatments due to their specificity and selectivity, which allows them to target cancer cells while leaving healthy cells unaffected.
As part of the development process drug safety and efficacy are key concerns for manufacturers. Stringent regulatory guidelines require thorough testing throughout the preclinical and clinical stages of therapeutic antibody development. To achieve this, robust methods are needed.
Overcoming Challenges in Antibody Discovery and Cell Line Development
Antibody–based cancer therapies must undergo a complex and lengthy development process to identify clones matching highly specific criteria. Although antibody development workflows are well established, many challenges can slow or obstruct these processes.
During high-content antibody screening, hundreds of candidate clones must be checked to identify those that match the desired affinity and specificity profile. Screening methods that are fast, sensitive, and accurate are required. Once the antibody is selected, a stable cell line must be identified to produce it reliably and at scale, to ensure consistent supply.
High-throughput screening methods, such as flow cytometry, can screen and identify application-specific antibodies. In contrast to ELISA, flow cytometry can be carried out directly on antigen-expressing cells to screen antibodies. To further improve throughput, the Bio-Rad ZE5 Cell Analyzer can process up to 100,000 events per second with no data loss, and a 96-well plate can be analyzed in less than 15 minutes in high-throughput mode, and a 384-well plate in less than 60. Visit our website to read more about antibody screening using the ZE5 Cell Analyzer, the high-throughput flow cytometer.
Monitoring Safety and Efficacy
Immunogenicity needs to be assessed throughout preclinical and clinical stages. Carefully designed bioanalytical assays are essential to fully characterize the efficacy, safety, and pharmacokinetic properties of candidate antibody drugs and to measure levels of anti-drug antibodies (ADAs). Robust, accurate, and reproducible ligand binding assays are key to achieving this, and their success depends on the quality of critical reagents. Highly specific anti-idiotypic antibodies, of consistent quality and with long-term availability, are required to ensure accurate measurements used in determining the selectivity, sensitivity, and specificity of the drug.
Bio-Rad has generated specific antibodies against many commercially available drugs for various diseases, including trastuzumab, ipilimumab, pembrolizumab, and nivolumab, as well as several hundred preclinical antibody-drug candidates. Custom antibodies were generated using Human Combinatorial Antibody Library (HuCAL®) technology and CysDisplay®, a proprietary method of phage display with guided selection methods to obtain highly targeted reagents. These custom antibodies can be used in pharmacokinetic studies and the development of immunogenicity assays. The antibodies are sequenced during the selection process and are strictly controlled to minimize or eliminate batch-to-batch variation, enabling bioanalysts to generate reproducible data for regulatory approval.
Tracking disease progression, as well as the safety and efficacy of the therapeutic agent, also relies on rapid, sensitive, and accurate ways of identifying and monitoring biomarkers. Multiplex and multiparameter assays offer a rapid way to assess multiple facets of a limited sample. For example, these assays may monitor cytokine and chemokine profile while also checking for drug-induced kidney toxicity or injury. These data facilitate informed decision making throughout the development process.
Monitoring gene expression and detecting mutations can identify disease biomarkers. Droplet Digital PCR (ddPCR) and quantitative PCR (qPCR; also called real-time PCR) can be used effectively to screen for mutations.
The QX ONE Droplet Digital PCR (ddPCR) System is a precise, all-in-one solution for ddPCR workflows.
Droplet Digital PCR and qPCR are also useful for quantification of host cell DNA (HCD or hcDNA). Manufacturers must quantify and report HCD levels, as safety and efficacy concerns are posed when established guideline levels are exceeded. Although qPCR is currently the most commonly used technique, Droplet Digital PCR has been shown to be more sensitive for host cell DNA quantification (Hussain et al. 2016) and is resistant to errors caused by inhibitors or other aspects affecting PCR efficiency. Droplet Digital PCR workflows also offer the option of eliminating the DNA extraction step, making the process more efficient. Learn more about how ddPCR Assays can support residual DNA quantification during antibody generation.
Manufacturing Pure Antibody-Mediated Therapies at Scale
Efficient production and manufacturing ensures that the correct antibodies are generated quickly while maintaining high quality and purity. Chromatography can be used to increase productivity, scale manufacturing, and purify antibodies. Purification involves multiple steps (capture, intermediate, and polish) using two or more resins, with the final product undergoing thorough quality control checks and testing to ensure compliance with regulatory requirements and standards. Bio-Rad offers a wide range of chromatography resins for process-scale purification, enabling the right resin to be selected depending on the final use of the antibody, desired purity, and cost.
Advancing Cancer Therapeutics
Biologics offer countless opportunities to improve human health. While significant progress has been made in understanding cancer and other diseases, new treatments, including complex antibody-based therapeutics in the form of antibody-drug conjugates and bispecific monoclonal antibodies, these innovative therapies can be challenging to develop and manufacture.
Bio-Rad offers a range of tools to support the identification of highly specific antibodies for therapeutic use, continuing to innovate and improve upon current methods to support scientists in monitoring efficacy and toxicity throughout the development and manufacturing process.
To learn more about how Bio-Rad can support your antibody research and biotherapeutics development, check out our antibodies page.
For more on therapeutic antibody discovery and development, listen to BioRad.io Episode 10: Next-Generation Therapeutic Antibody Discovery.
References
Hussain M et al. (2016). A direct Droplet Digital PCR method for quantification of residual DNA in protein drugs produced in yeast cells. J Pharm Biomed Anal 123, 128–131.