Therapeutic antibodies, an innovation at the heart of precision medicine

When we think of antibodies, we generally picture those produced by the immune system to fight infection and disease. But antibodies can also be synthesized in the laboratory to offer new therapeutic options—these are known as therapeutic antibodies. Initially conceived for use in oncology, they are now one of the cornerstones of precision medicine and a first-line treatment for many diseases, including cancer and neurological disorders. Here we take a closer look at these innovative therapies, which are rapidly transforming the way many patients are being treated.

Therapeutic antibodies: When the pharmaceutical industry draws inspiration from the immune system

Antibodies are large molecules produced by the immune system in response to biological attacks (fungi, viruses, bacteria, foreign cells, etc.), primarily by B lymphocytes and plasma cells. It is estimated that the human body has the capability to produce up to a quintillion—or a billion billion—unique antibodies⁴.

Antibodies can also be created in a lab from living cells, which makes them a type of biopharmaceutical. As with antibodies created naturally by the body, those made in a lab target specific disease agents or biological mechanisms involved in the progression of a disease.

There are different types of therapeutic antibodies:

• Monoclonal (or monospecific) Antibodies (mAbs): Essential in the treatment of cancer, autoimmune disorders, and infectious diseases, monoclonal antibodies bind to the target antigen or marker in a highly specific way, and by doing so they neutralize the action of the target – e.g. By blocking the function of a protein promoting inflammation or a protein which helps cancer cells survive.
• Bispecific Antibodies (BsAbs): Designed with two different “arms” that can each bind to a different antigen, these antibodies offer several advantages. Unlike monospecific antibodies, which only target one antigen, bispecific antibodies can simultaneously interact with two antigens present on the cells they are designed to eliminate. By targeting two antigens, or epitopes, such treatments can induce multiple and synergistic physiological or anti-tumor responses. At Servier, we use this technology predominantly in the development of oncology treatments.
• Antibody Drug Conjugates (ADCs): These compounds consist of a monoclonal antibody (mAb) attached to an active ingredient via a linking agent, or “linker.” The antibody binds to the surface of the target cells, allowing the conjugated drug substance to enter the cell and release the active molecule directly inside. Although the majority of approved ADCs and those in development target various types of cancer, these complex therapies show considerable potential for treating other diseases.

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Examples of the mechanisms of action of therapeutic antibodies in oncology (figure images courtesy of Pavlos Englezou)

Therapeutic antibodies: A key technological building block for advancing precision medicine

Therapeutic antibodies play a central role in precision medicine. Their unique properties make them complementary to other targeted therapies that are currently being developed, such as small molecules and RNA therapies, including antisense oligonucleotide (ASO) therapies. The potential of therapeutic antibodies lies in a number of major advantages:

• Stable binding and extended action: Once bound to their target, therapeutic antibodies are normally strongly and stably attached. Combined with a long half-life, this results in sustained efficacy ranging from a few weeks to several months. Injections can therefore to be spaced out, which can significantly improve patients’ quality of life and encourage therapeutic adherence.
• High versatility: Therapeutic antibodies can be tailored to the biological characteristics and needs of individual patients (injection volume, frequency of administration, etc.), thereby optimizing efficacy and improving patient tolerance.
• High selectivity: They target specific diseased cells or pathological proteins. As a result, healthy tissue is spared, reducing the side effects that may be associated with other broad-spectrum treatments, such as chemotherapy. This selectivity also minimizes interactions with other drugs, which is a clear advantage for patients on multiple medications.

“Therapeutic antibodies are a unique drug modality in precision medicine, which is increasingly targeted and tailored to the needs and biological characteristics of patients, and antibodies offer undeniable advantages, such as high selectivity, prolonged efficacy, and versatility. They have particularly promising development prospects and offer hope for patients with cancer or rare genetic diseases.”

Claus Haase, Head of Biologics Drug Design & Senior Vice President of Symphogen, Servier’s Antibody Center of Excellence

However, in order for patients to benefit from the full potential of therapeutic antibodies, the pharmaceutical industry must still overcome several challenges.

First, as a type of biopharmaceutical, the production of therapeutic antibodies involves complex processes that rely on living cell systems.

Second, their administration can trigger an “anti-drug” immune response from the body against the antibodies, leading to a loss of efficacy and possible adverse effects. At Servier we try to overcome this problem by developing fully human therapeutic antibodies or by ”humanizing” non-human antibodies which is a technology that makes them more similar to those naturally produced by humans, which will greatly reduce the risk of such immune responses.

Furthermore, some antibody-drug conjugates are also associated with specific toxicities, particularly in the lungs, eyes, and skin. Therefore, their use requires close monitoring and the implementation of mitigation strategies. Due to the intrinsic toxicity, there is a limit to the maximum dose that can be administered, which may potentially reduce the effectiveness of therapy.

And lastly, therapeutic antibodies cannot be administered orally, unlike other types of targeted therapies. In the case of long-term treatments, the need for injections can be a barrier to patients’ adherence to treatment.

[1] Lyu X, Zhao Q, Hui J, Wang T, Lin M, Wang K, Zhang J, Shentu J, Dalby PA, Zhang H, Liu B. The global landscape of approved antibody therapies – https://pmc.ncbi.nlm.nih.gov/articles/PMC9535261/#:~:text=The%20Umabs%2DDB%20shows%20that,not%20included%20in%20our%20statistics.
[2] Designing antibodies as therapeutics – Paul J.Carter Arvind Rajpal – https://www.cell.com/cell/fulltext/S0092-8674(22)00699-7?_returnURL=https%3A%2F%2Flinkinghub.elsevier.com%2Fretrieve%2Fpii%2FS0092867422006997%3Fshowall%3Dtrue – consulted on 20.03.25
[3] Mythili Shastry et al. Rise of Antibody-Drug Conjugates: The Present and Future – https://ascopubs.org/doi/10.1200/EDBK_390094
[4] Decoding the variety of human antibodies – National Institute of Health – https://www.nih.gov/news-events/nih-research-matters/decoding-variety-human-antibodies#:~:text=Based%20on%20their%20findings%2C%20they,one%20million%20trillion%2C%20unique%20antibodies. – consulted on 20.03.25