Cancer Immunotherapy - Types and Side Effects

Introduction:

Cancer refers to the development of abnormal cells in the body. It harms the health of an individual by causing damage to the immune system. The immune system identifies and kills the cancer cells. A strong immune response is highly necessary to fight against cancer. But the weakened immune response in people with cancer results in cancer spreading at a faster pace. The immune system alone cannot defend against cancer, so additionally, certain treatment modalities are utilized to fight against it. Immunotherapy is one such treatment modality where the immune system of an individual is utilized and stimulated to fight against cancer.

What Is Immunotherapy?

Immunotherapy is one of the cancer treatment modalities that utilize and boosts the immune system to fight against cancer. The different ways by which immunotherapy is done include;

• By utilizing one's immune system and further it gets stimulated or boosted to fight against cancer.

• By using laboratory-made substances like vaccines that mimic the action of the immune system and stimulate it to kill the cancer cells.

Promising results are seen in people with cancer who received immunotherapy. Immunotherapy can be used along with other treatment approaches like chemotherapy and radiation therapy. New advancements in immunotherapy are discovered by scientists to provide better cancer treatment. Not every individual is ideal to have immunotherapy as a part of their cancer treatment. Only your healthcare provider can suggest whether you can undergo immunotherapy or not.

Can All Types of Cancers Be Treated With Immunotherapy?

Immunotherapy cannot be used as a treatment approach for all cancers. It can be used in the treatment of certain cancers like,

• Lung cancer (cancer that occurs in the lungs, especially in people who smoke).

• Breast cancer (cancer that begins in the cells of the breast).

• Cervical cancer (cancer that occurs in the lowermost part of the uterus, which is the cervix).

• Skin cancer (cancer where abnormal growth of skin cells is seen).

• Lymphoma (cancer of the lymphatic system).

• Bladder cancer (cancer that begins in the cells of the bladder).

• Leukemia (blood cancer).

• Brain tumor (growth of abnormal cells in the brain is seen ).

• Head and neck cancer (cancer that occurs in the mouth, sinuses, nose, lips, throat, larynx, and salivary glands).

• Colorectal cancer (cancer of the colon or rectum).

What Are the Different Types of Cancer Immunotherapy?

The different types of cancer immunotherapy include,

Immune Checkpoint Inhibitors:

T-lymphocytes, or T-cells being an immune system component, identifies the abnormal( cancerous) cells in the body using their receptors (T-cell receptors). These T-cell receptors bind themselves to the abnormal cell and start signaling the T-cell to release molecules that destroy the cancer cells. T-cells also have receptors that can restrain their function other than activating T-cell receptors. Such receptors are called “checkpoints.”

Activation of these checkpoints prevents cancer cells from getting killed by T-cells. Cancer cells stop T-cell signaling by using these checkpoints. This further stops cancer cell killing by T-cells. Immune checkpoint inhibitors kill cancer cells by preventing this manipulation of cancer cells which stops T-cell signaling. Different checkpoint inhibitors are used, and many discoveries in immunotherapy treatment in immune checkpoint inhibitors are still under development. Some of the common immune checkpoint inhibitors include:

1. PD-1 Inhibitors:

These inhibitors inhibit PD-1 checkpoint protein. The different PD-1 inhibitors

include-

• Nivolumab (Opdivo).

• Cemiplimab (Libtayo).

• Pembrolizumab (Keytruda).

2. PD-L1 Inhibitors (Inhibits PD-L1 protein):

• Atezolizumab (Tecentriq).

• Durvalumab (Imfinzi).

• Avelumab (Bavencio).

3. CTLA-4 Inhibitor (Inhibits CTLA-4 protein):

• Ipilimumab (Yervoy).

Adoptive Cell Therapy:

In adoptive cell therapy, one's own immune cells (T-cells) are collected and grown in the lab, and then these cells are given back to them intravenously. It is also referred to as immune cell therapy, adoptive immunotherapy, and cellular immunotherapy. The types of adoptive cell therapy include:

CAR (Chimeric Antigen Receptor) T-cell Therapy:

A treatment in which the T-cells are collected from the blood and grown in the lab and modified. The T-cells are reprogrammed, and now they produce a special receptor called chimeric antigen receptors on the T-cell surface. These receptors are then reinfused into that person's blood. It helps in treating blood cancers and certain other types of cancer.

Some of the CAR T-cell therapies approved by FDA include:

1. Tisagenlecleucel (Kymriah).

2. Lisocabtagene maraleucel (Breyanzi).

3. Idecabtagene vicleucel (Abec Ma).

4. Axicabtagene ciloleucel (Yes Carta).

5. Brexucabtagene autoleucel (Tecartus).

Some of the other adoptive cell therapies include NK (natural killing) cell therapy and Tumor-infiltrating lymphocytes (TILs) therapy.

Monoclonal Antibodies:

Monoclonal antibodies are antibodies developed in laboratories from their identical parent immune cells. Many monoclonal antibodies are used to treat cancers. They typically function like antibodies that bind to the cancer cells and engulf them. The other way through which it functions is by blocking the growth signals that block cancer cells' growth. It is used in treating cancers like stomach cancer, leukemia, colorectal cancer, etc. Monoclonal antibody infusion therapy is even beneficial in treating COVID-19. Some of the common examples of monoclonal antibodies used to treat cancer include:

1. Bevacizumab (Avastin).

2. Rituximab (Mabthera).

3. Trastuzumab (Herceptin).

4. Pertuzumab (Perjeta).

Cancer Vaccines:

Cancer vaccines are like typical man-made vaccines that help in the fight against cancer. It makes the immune system exposed to the antigen and makes antibodies for it, and kills it. Examples of cancer vaccines include;

• Hepatitis B vaccines (used in liver cancer).

• HPV (human papillomavirus) vaccine (protects from cervical and penile cancers).

• Sipuleucel-T (Provenge) - It is used to treat prostate cancers.

• Talimogene laherparepvec (T- VEC) - It is used to treat melanoma skin cancer.

Immunomodulators:

Cancer immunomodulators are drugs that help in treating a few cancers and other conditions like multiple myeloma. It acts by modifying the immune response either by increasing or decreasing antibody production. Examples of cancer immunomodulators include:

• Thalidomide.

• Lenalidomide.

• Pomalidomide.

• Imiquimod.

Oncolytic Viruses:

Oncolytic viruses are those viruses that specifically target and infect cancer cells. They can be used as immunotherapy. It helps in the fight against cancer in two ways;

1. Specifically targeting and infecting cancer cells further kills cancer cells.

2. Releasing antigens from killed cancer cells further develops immune response by recognizing the particular antigen and killing it.

Examples of oncolytic virus in cancer treatment include T-VEC (talimogene laherparepvec) in treating metastatic melanoma.

What Are the Side Effects of Immunotherapy?

The common side effects of immunotherapy include;

• Fatigue.

• Fever or moderate flu-like symptoms.

• Nausea and vomiting.

• Headache.

• Weight loss and loss of appetite.

• Skin rash.

• Diarrhea.

• Difficulty in breathing.

Severe life-threatening complications are seen in people with cancer receiving prolonged immunotherapy. Cytokine storm is one such life-threatening complication seen as a side effect of immunotherapy.

Who Is an Ideal Candidate to Receive Cancer Immunotherapy?

Not all people with cancer are ideal to receive immunotherapy. Only your healthcare provider can decide whether you are an ideal candidate to receive immunotherapy. It is decided on the following basis:

1. Age: Age is one of the primary factors in deciding whether the candidate is ideal to receive immunotherapy or not. Immunotherapy is not usually suggested in elderly people aging more than 60. This is because immunotherapy may be ineffective at times, and it also causes difficulties for them.

2. Stage and Type of Cancer: Your healthcare provider will decide whether immunotherapy will be effective or not based on the stage and type of cancer. In certain cases, doctors may suggest immunotherapy in the initial stages of cancer, whereas on the other hand, it may be suggested in later stages too. Immunotherapy is not given for all cancers since it has not shown any proven effects in some cancers. It is usually given in lung cancer, liver cancer, skin cancer, leukemia, etc.

3. Genomic Testing: Genomic testing results help analyze the ideal candidate to receive immunotherapy. Your doctor will analyze the genomic test results and decide whether immunotherapy can work for you or not.

4. Pre-existing Diseases: If the person is suffering or undergoing treatment for any pre-existing diseases, then the doctor may avoid giving immunotherapy. Immunotherapy may either be ineffective or do not provide promising results in such candidates. People who have an autoimmune disorder are not ideal for receiving immunotherapy.

5. Organ Transplantation: Healthcare providers will inquire whether you have undergone any organ transplantation or not. Immunotherapy is not carried out in people who had organ transplantation.

Is It Safe to Get Immunotherapy?

Immunotherapy shows promising results in treating people with cancer. However, it can contribute to some side effects too. It is often considered a better approach than chemotherapy and radiation therapy for prolonged intervals. Do consult your healthcare provider to know more about immunotherapy, and he will decide whether immunotherapy will be effective, safe, or ideal for you.

Conclusion:

Immunotherapy shows promising results in the treatment of cancer. They act by stimulating or boosting the immune system to fight against cancer. Immunotherapy is not used in treating all cancer since proven effects of immunotherapy are not seen in some cancers. New advancements in immunotherapy are developed to find the best possible cancer treatment.