In the field of drug development, one of the major challenges is the distribution of biologicals such as antibody drugs in tumor tissue. The heterogeneous distribution of antibody drugs in tumor tissue has been recognized as a major issue for immunotherapy. Transport of biologicals, such as antibody therapeutics, into tissues is a complex process involving a combination of factors. In solid tumors, functional lymphatic vessels are rare, leading to an increase in hydrostatic pressure, reducing the propensity of the convection gradient to drive macromolecules into the tumor. Traditional methods for assessing drug distribution have limitations, and a more accurate and comprehensive understanding of drug distribution in tumor spheroids is needed. Our in vitro Antibody Pharmacokinetics Assay can help overcome these challenges.
Other Factors Affecting Antibody Drug Distribution
The distribution of antibody drugs in tumor tissue is a complex process that involves several factors.
- One of the major factors that affect the distribution of antibody drugs is the tumor microenvironment. The tumor microenvironment is characterized by the presence of various cells, including cancer cells, stromal cells, and immune cells. These cells secrete various factors that can affect the distribution of antibody drugs in the tumor tissue. For example, the presence of extracellular matrix proteins can hinder the penetration of antibody drugs into the tumor tissue.
- Another factor that affects the distribution of antibody drugs is the size of the antibody molecule. Large antibody molecules have difficulty penetrating the tumor tissue due to their size. This is especially true for solid tumors, where the interstitial pressure is high, making it difficult for large molecules to penetrate the tumor tissue.
- Traditional methods for assessing drug distribution, such as animal studies, have limitations. Animal studies are costly, time-consuming, and may not accurately reflect the distribution of antibody drugs in humans. In addition, animal studies may not be able to accurately predict the efficacy of antibody drugs in humans.
Our In Vitro Antibody Pharmacokinetics Assay
Our in vitro Antibody Pharmacokinetics Assay offers a more accurate and comprehensive understanding of drug distribution in tumor spheroids. The assay involves generating free-floating tumor spheroids, treating them with antibody therapeutics at various concentrations, fixing them at specified time points, labeling the antibody with fluorescent secondary to label therapeutic antibody, applying tissue clearing to render tumor spheroids transparent, high content confocal imaging, and analysis of resultant images to assess distance and quantity of antibody penetration into tumor spheroid.
The assay measures the distribution of biologicals, including antibody drug conjugates, antibody fragments, alternate domain antibodies, affibodies, and nanobodies. The test article concentration involves an 8-point assay and a single point assay, with custom concentrations available. Time points include 0.5 hr, 1 hr, 2 hr, 4 hr, 8 hr, 24 hr, 48 hr, with custom time points available. Three replicates per concentration are required, with 0.5% DMSO as the vehicle control and anti-β-integrin as the positive control. Antibody concentration is measured as a mean of pixel intensity in concentric bands of decreasing radius from the edge of the tumor spheroid into the center.
The resultant data includes distribution curves, velocity curves, TD50 (time to distribute to 50% of total) values, and concentration-time curves (measured as AUC). Representative data includes confocal sections from the center of HepG2 tumor spheroids depicting the relative distribution of anti-β-integrin antibody at various concentrations and times, a representative curve depicting parameters used for quantitation of antibody distribution into tumor spheroids, and quantitative measurements of the extent of distribution of antibody into tumor spheroids. The assay also measures the dose and time dependence of velocity of antibody distribution and time to distribute to 50% of spheroid radius (DT50) and maximum distance of penetration.
Why Work with Us?
The distribution of biologicals such as antibody drugs in tumor tissue is a complex process that involves several factors. Traditional methods for assessing drug distribution have limitations, and a more accurate and comprehensive understanding of drug distribution in tumor spheroids is needed. Our in vitro Antibody Pharmacokinetics Assay offers a more accurate and comprehensive understanding of drug distribution in tumor spheroids, which can improve drug development outcomes. By working with us, pharmaceutical companies, pharmaceutical scientists, biochemists, medicinal chemists, pharmacologists, and toxicologists can accelerate the drug discovery and development process by providing advanced imaging and cell culture tools. For more information about this assay, please reach out to a member of our team to get started today!