Drug Discovery and Efficacy Evaluation Using Cancer Immunological Assays

Importance of assays in cancer immunotherapy

Currently, "cancer immunotherapy," such as immune checkpoint inhibitors and CAR-T cell therapy, is used as a pillar of cancer treatment. From this perspective, in the drug discovery screening process,An in vitro model (cancer immunology assay) is essential to evaluate how candidate compounds activate immune cells and inhibit tumor cell immune evasion mechanisms.It can be said that establishing an appropriate assay (evaluation system) is a very important process that affects the decision to move to clinical trials and the success rate of development.

Types of Representative Cancer Immunological Assays and Evaluation Methods

Killing assay (cytotoxicity test)

such as T cells and NK cellsMethods for measuring the ability of effector cells to directly attack and kill cancer cellsThis is called a "killing assay (cytotoxicity assay)." Although it was common in the past to use methods like the LDH assay, which measures enzymes released with cell death, in recent years, monitoring using flow cytometry and real-time cell analysis systems has become mainstream.

ADCC/CDC assay (Antibody-Dependent Cell-mediated Cytotoxicity/Complement-Dependent Cytotoxicity)

ADCC/CDC assay (antibody-dependent cell-mediated cytotoxicity/complement-dependent cytotoxicity)A method mainly used for evaluating the efficacy of antibody drugsADCC and CDC are both immune mechanisms where antibodies that have entered the body destroy target cells like cancer cells or virus-infected cells. However, there are differences, such as in ADCC, NK cells and macrophages carry out the attack, while in CDC, antibodies bind to proteins in the blood (complement), leading to destruction.

Reporter assays are also used as a convenient method for measuring biological responses. While various reporter genes are available, one of them, luciferase, is used to construct bioluminescent reporter assays that offer high quantitativeness and sensitivity, along with a wide dynamic range, detectable by measuring light emission.

Cytokine production and secretion analysis

A method for evaluating immune status and inflammatory responses by measuring the amount of proteins (such as cytokines) released when immune cells are activated.Representative methods include ELISA (enzyme-linked immunosorbent assay), which quantitatively detects antigens in a sample, ELISPOT (enzyme-linked immunospot) assay, which detects cellular secretion activity at the single-cell level, and multiplex assays, which can measure multiple target molecules simultaneously.

Analysis of binding and expression of immune checkpoint molecules

Methods for evaluating the expression and function of molecules that act as "immune brakes," such as PD-1/PD-L1.To confirm whether cancer cells can evade the immune system, we will measure the extent to which our developed antibody drug inhibits the binding between target molecules using a Binding Assay.

Advancement of Cancer Immunological Assays Using Latest Technologies

Utilization of Organoids (PDOs) and Spheroids

In traditional planar (2D) cell culture, there has been a significant challenge of difficulty in reproducing the complex tumor microenvironment (TME). However, currentlyEvaluation in an environment close to in vivo using three-dimensional models such as patient-derived cancer organoids (PDOs) and co-culture of immune cellsbecause it is now possible,Improved drug effect prediction accuracyThe company is doing so.

High-throughput processing with AI and image analysis technology

In recent years,AI-based image analysis and introduction of High Content Screening (HCS)This is being advanced. This will enable the quantitative and rapid analysis of subtle changes in cell morphology and apoptosis (programmed cell death) by tracking them over time using 3D imaging. Therefore, an improvement in efficiency is expected when screening for promising drugs from a vast number of candidate compounds.

Challenges of In-house Development and Benefits of Utilizing CRO (Contract Research Organization)

Challenges in Assay Development

To establish an in-house cancer immunotherapy assay, stable preparation of primary cultured cells (e.g., PBMCs), control of inter-donor variability, and optimization of co-culture conditions are required, among other things.Requires advanced expertisewill be. Furthermore, to introduce and maintain advanced specialized equipment such as real-time cell analyzers and 3D imaging devices,This also increases costs significantly, presenting a major hurdle for pharmaceutical companies and research institutions.This is the current situation.

Benefits of Commissioning Trials with a Professional CRO

Outsourcing studies to a CRO specializing in tumor immunology can lead to solutions for the aforementioned challenges.In addition to conducting stable tests by experts, precise data acquisition using the latest equipment.becomes possible. As a result,Researchers can focus on core tasks, including lead compound selection.This will allow for benefits such as accelerating drug discovery.

What's next for cancer immunoassays?

Going forward, it will be possible to not only simply kill cancer cells but also to achieve a "complex reproduction of the tumor microenvironment (TME)," including surrounding blood vessels and immunosuppressive cells such as MDSCs and Tregs.Assays using 3D complex co-culture models that are closer to biological systems will become mainstream.This is conceivable.

Furthermore, as assays using patient-derived organoids (PDOs) become more widespread, they can predict patient drug response prior to clinical trials,Contribution to "personalized medicine (precision medicine)" for selecting appropriate treatment methods and predicting resistance for each individualis expected.

and to keep up with advanced cancer immunoassays that are rapidly evolving, rather than building from scratch in-house,The key is to actively utilize external CRO services, which possess specialized technical capabilities and a wealth of experience.This can be said. This point is expected to become the standard strategy for the successful development of new drugs.