Monoclonal antibody drugs have been in the clinician’s toolbox for several decades and are highly promising treatment options for infectious diseases, pathologies of the immune system and many types of cancer.
Moreover, over a thousand clinical trials involving monoclonal antibodies (mAbs) are currently being carried out in the USA alone. The collected data is expected to result in several novel approvals by the Food and Drug Administration (FDA) to make even more and improved mAbs available to patients.
This article will explain the general concept of therapeutic monoclonal antibodies and then focus on their use in oncology to fight grave cancerous diseases before touching on other fields of application for monoclonal antibody drugs.
Monoclonal antibody treatments involve the intravenous infusion or subcutaneous injection of synthetic proteins that are very closely related to natural antibodies that patrol in our bodies to seek pathogens and degenerated, malign cells and highlight them for T cells to destroy them.
Subscribe to our Newsletter
Get all the latest updates, and learn about our advancements in antibody production.
Subscribe now
In vivo, antibodies are secreted by B cells which are key immune cells in the human adaptive immune response. In contrast, therapeutic monoclonal antibodies are developed in vitro until their properties are perfected for their respective application. Of course, this includes the affinity and specificity toward their target antigens, which might be surface features of a pathogen, cancer cells, or a receptor involved in the regulation of immune cells in the case of checkpoint inhibitors which are immunotherapies.1
Hence, mAbs are considered so-called targeted therapies, because they are made to be very selective for the pathogenic or malignant cells. In contrast, traditional chemotherapies are cytotoxic to every type of cell in the body, and cancer cells are just a little bit more susceptible to them, just as e. g. blood forming tissues, often leading to severe side effects.
The application of mAb drugs in cancer therapy is usually by injection or monoclonal antibody infusion into a vein at a specialized healthcare provider or less commonly in outpatient care. Depending on the type of cancer and the specific mAb drug, the application takes more than about an hour with a monitoring period to ensure tolerability. How often and in which frequency the treatment is repeated also varies with cancer type and mAb drug.
The types of cancer that are treated with mAb drugs are varied and some mAbs are used for more than one cancer:
Monoclonal antibody therapies that are currently in use may have one or several mechanisms of action to fight cancer cells or help the body’s own immune system to fight them:
As is true for every therapy, side effects are possible with therapeutic mAbs. They range from common and mostly harmless irritation at the site of injection to rare but severe adverse effects:
Many mAbs are currently in use for oncologic indications. Their mechanisms of action and conditions in which they work best are very varied. Hence, we want to give a few examples of therapeutic mAbs and how they are applied:
Bevacizumab: anti-VEGF, reduces the growth of new blood vessels in tumors and slows their growth; since this is a more general mechanism of action, it is used in various solid tumors
Cetuximab: anti-EGFR, many cancer cells have an overabundance of EGF receptors on their surface, thus having higher growth rates; blocking them in turn reduces the growth of cancer cells; used in colorectal and head and neck cancers
Gemtuzumab ozogamicin: a molecular combination of an antibody and the very potent cytotoxic agent ozogamicin; is has a high affinity to the CD-33 protein on most leukemic blast cells and decreasingly so on less developed normal hematopoietic cells; used in acute myeloid leukemia
In addition to the broad application of mAb therapeutics in oncology, this drug class finds great use in autoimmune conditions such as rheumatoid arthritis and Crohn’s disease.
Moreover, the pandemic caused by the SARS-COV-2 coronavirus spawned concerted efforts to quickly develop neutralizing monoclonal antibodies against COVID-19 as a complementary strategy to the COVID-19 vaccine and the use of traditional antiviral drugs such as remdesivir.
Prior the the current era of omicron variants, several mAbs received emergency use authorizations (EUA) for the treatment of COVID-19 infection in patients with risk factors and cases of severe COVID-19:
Currently, only Bebtelovimab is recommended due to its remaining activity against the circulating Omicron variants.