Providing insights into cancer treatment success
Monitoring the effectiveness of immunotherapy
The therapies available to treat cancer are continuously advancing, and immunotherapy is now used more and more frequently in conjunction with traditional treatments (such as radiotherapy and chemotherapy) to give patients the best chance of long-term remission. Unlike chemotherapy, which damages all fast-dividing cells, immunotherapy takes a targeted approach by stimulating the patient’s own immune system to recognise and destroy tumorous cells. This method typically involves fewer side effects for the patient, as healthy cells (such as those in the skin, nails, hair, and reproductive system, where normal cell division is rapid) are not killed in the process
One such immunotherapy, CAR T-cell therapy, is increasingly used to treat cancers characterised by malignant B-cells (B-cells which proliferate uncontrollably). It uses the patient’s T-cells – a type of white blood cell that plays a central role in the immune system – to target B-cells in the blood.
With the CAR T-cell therapy approach, T-cells collected from the patient’s blood are genetically modified with a special receptor, called the “Chimeric Antigen Receptor (CAR)”, which recognises a protein found on the surface of malignant B-cells (most commonly the CD19 protein). The modified T-cells are multiplied and then infused back into the patient’s blood. Once inside the body, these modified CAR T-cells bind to, and thereby inactivate, B-cells with the CD19 protein.
This treatment is now a recognised standard for relapsed or treatment-resistant B-cell cancers, such as pre-B-cell acute lymphoblastic leukaemia and B-cell lymphoma. Thousands of clinical trials are underway across the world focussing on the area of immunotherapies, and CAR T is considered one of the fastest-growing areas in oncology.
To help improve patient outcome, the persistence and expansion of the genetically modified T-cells in the body should be monitored. Monitoring data allows for a better understanding of the treatment’s effectiveness and optimal duration, while also ensuring that the modified cells are not continuing to proliferate in the body and thereby risking harm to the patient.
Eurofins Viracor has developed and validated a multiplexed quantitative real-time PCR (qPCR) assay, called ExPeCT™ CAR T-Cell Persistence Assay, which can monitor how many modified T-cells are present in the body by targeting a unique antibody fragment in those cells, called FMC63. The assay was launched in 2023, becoming the first commercially available monitoring assay to monitor CAR T-cell expansion and persistence in patients being treated with this therapy. By providing clinicians with an accurate and comprehensive assessment of the CAR T-cell population in the patient’s body, the assay guides treatment decisions and helps to assess long-term remission potential for patients.
The science behind
By quantifying CAR vector copies in patient samples (both copies/ug and copies/mL), the ExPeCT™ assay enables longitudinal monitoring of CAR T-cell levels post-infusion, which is critical for evaluating therapy effectiveness, managing relapse risk, and identifying adverse events such as cytokine release syndrome (CRS), Immune Effector Cell-Associated Neurotoxicity Syndrome (ICANS), or graft-versus-host disease (GvHD).
There are numerous CAR T-cell immunological therapies in the design and development phase targeting different constructs, including FMC63. The Anti CD-19 FMC63 construct target is the first approved therapeutic target. Eurofins Viracor is currently developing two additional CAR T-Cell Immunotherapeutic assays that target different constructs expressed on B-cells.
