Science Series #1: Immunotherapy

What is the Immune System?

The immune system is a set of organs, cells, and substances that protect the body from infections and diseases. It keeps the body safe from harm by constantly keeping tabs on the substances found in the body. When a new virus attempts to infiltrate the body, the immune system is alerted and attacks the foreign organism. Because the body’s defenses remember how to eradicate a disease that was previously marked as foreign, the body gains immunity; this is called acquired immunity, which differs from innate immunity, an inherent protection that doesn’t require exposure for the immune system to remember. That is why chickenpox can only be contracted once in a lifetime.

(Source: National Center for Biothecnology Information)

How does the immune system react to cancer?

There are ways to stimulate the immune system to increase its effectiveness towards cancer. Immunotherapy, also known as biologic therapy or biotherapy, is a treatment that uses the body’s immune system to fight harmful substances. This is done by either stimulating the immune system to work harder or smarter to attack diseases, or adding supplemental man-made immune system proteins. Although immune systems fight off bacteria, viruses or parasites as foreign organisms, these processes can also be geared towards cancer cells.

(Source: American Society of Clinical Oncology)

What is Cancer Immunotherapy?

There are ways to stimulate the immune system to increase its effectiveness towards cancer. Immunotherapy, also known as biologic therapy or biotherapy, is a treatment that uses the body’s immune system to fight harmful substances. This is done by either stimulating the immune system to work harder or smarter to attack diseases, or adding supplemental man-made immune system proteins. Although immune systems fight off bacteria, viruses or parasites as foreign organisms, these processes can also be geared towards cancer cells. (Source: American Society of Clinical Oncology)

Types of cancer immunotherapy

There are five main types of cancer immunotherapy.

(Source: American Cancer Society)

Monoclonal antibodies are a man-made version of the immune system proteins called antibodies that help fight infections. These artificial proteins can bind to a specific target. In the case of cancer immunotherapy, these proteins can flag cancer cells as dangerous, making it easier for the immune system to destroy them.

One of the reasons why the immune system has trouble identifying cancer is because there are inhibitors or “brakes” that prevent the body’s defenses from attacking what it regards as familiar. These molecules found on certain immune cells are the immune checkpoints; and cancer cells might sometimes use these checkpoints to avoid being attacked by the immune system. Therefore, by inhibiting them, using drugs that specifically target these checkpoints, the immune system can better recognize and attack cancer cells.

Vaccines are treatments that familiarize the body with specific organisms and diseases to produce or artificially increase immunity. Cancer vaccines can be therapeutic or preventive. Therapeutic vaccines are designed to help the immune system better recognize cancer cells as dangerous in order to destroy them. There are also preventive vaccines related to cancer such as the HPV vaccine. Since HPV is the most common cause of cervical cancer, this vaccine prevents this cancer from arising.

T cells are regarded as the workhorses of the immune system since they are crucial to the immune response. CAR T cell therapy involves taking T cells from a patient’s blood and genetically engineering them, adding the chimeric antigen receptors (CARs), which make them CAR T-cells. These receptors allow the engineered cell to recognize specific cancer-related antigens and attack cancer cells. Once the CAR T cells are obtained, they are multiplied and infused back into the patient; where they can bind with cancer cells, multiply and destroy them.

These treatments do not target cancer cells specifically, though they stimulate the immune system in a general way, improving the immune response against cancer cells. These options are either themselves given as a cancer treatment or as adjuvants, being and adjuvant a supplement to the main treatment. A commonly used non-specific treatment is the cytokines, which are chemicals produced by immune cells, that are essential in the growth, control, and activity of immune cells and blood cells.

Doing Our Part

Out of the five cancer immunotherapy types listed above, JCWO’s research and development is in the domain of cancer vaccines. This work in immunotherapy began decades ago when Dr. Jacinto Convit successfully developed and applied therapeutic vaccines for Leprosy and Cutaneous Leishmaniasis, the latter being widely used in Venezuela and other Latin-American countries. Years later, when he became interested in cancer, Dr. Convit realized there were immunological similarities between the development of this disease and infectious diseases such as Leprosy and Leishmaniasis, which led him to perform pre-clinical tests in several animal models and publish a proposal for a breast cancer autologous vaccine. During his last years of life, he completed a small pilot human study in advanced breast cancer female patients, observing positive results. To preserve and continue his work, JCWO, carried out further studies to validate the efficacy and toxicity of this therapy. In late 2018, the FDA approved the vaccine, named ConvitVax, to initiate the clinical phase and since then two trials are being organized under partnership agreements with health institutions in developing countries.

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