Development of immunotherapy in cancer treatments

Contributed by Dr. Indoo Ammbulkar, Senior Medical Oncologist, HCG Cancer Centre Mumbai
Cancer is the deadliest disease and leading cause of death worldwide. Over the years, ability to test and treat the disease has significantly improved. More people who get cancer are living longer. Some are being cured. Exhilarating advances are paving the way to better treatment outcomes and possibly more cures. Conventional medical treatment of cancer includes chemotherapy, targeted therapy, and hormone therapy. Immunotherapy is a promising new type of advanced cancer treatment which is the great breakthrough to now existing treatment. Immunotherapies have revolutionized cancer treatment. Immunotherapy is effective for the treatment of a broad range of cancers and can facilitate complete and resilient tumor regression.
Immunotherapy is a type of cancer treatment that helps in boosting the body’s natural defences to fight cancer. It makes use of substances either made naturally by the body or created in the laboratory. This can be done in few ways:
•    Stimulating or boosting, the natural defences of the immune system so it works harder or smarter to find and attack cancer cells.
•    Developing substances in a lab that are just like immune system components and using them to help restore or improve how your immune system works to find and attack cancer cells 
How Immunotherapy helps to treat cancer  
Immunotherapy is a type of cancer treatment that helps the immune system of the human body fight cancer. The immune system comprises of a compound process a body uses to fight illness. This process involves your cells, organs, and proteins. Immunotherapy is a type of biological therapy. It is a type of treatment that treats cancer through substances made from living organisms. 
In the last few decades immunotherapy has become an essential part of treating certain types of cancer. Different types of immunotherapy work in different ways. Certain immunotherapy treatments help the immune system stop or slow the growth of cancer cells. Others help in destroying cancer cells or stop the cancer from spreading to other parts of the body. Immunotherapy treatments can be used by combining with other cancer treatments or alone.
There are different types of immunotherapies. They include:
•    Monoclonal antibodies and tumor-agnostic treatments 
•    Oncolytic virus therapy
•    T-cell therapy
•    Cancer vaccines

Improving the efficacy of immune check point inhibitors to achieve precision anti-tumor therapy is a major direction of immunotherapy research. Certain biomarkers can predict the efficacy of response to immunotherapy like PD1/PDL1, tumour mutation burden, mismatch repair deficiency, tumor infiltrating lymphocytes and microsatellite instability.

Three anti-PD-1 antibodies have been approved by the FDA: pembrolizumab, nivolumab and cemiplimab. Three anti-PD-L1 antibodies have been approved by the FDA: atezolizumab, durvalumab and avelumab.  As of now, six anti-PD-1/PD-L1 monoclonal antibodies have been approved with supplemental indications across 19 cancer types and two tissue-agnostic conditions.
There are as many as 19 cancer types which can be treated with immunotherapy. Some of them include, breast cancer, colon cancer, urinary bladder cancer, lung cancer, kidney cancer, liver cancer, lymphoma, throat/oral cancer etc. CAR T cells have been effective in leukemia and lymphoma. Promising results have been obtained in the treatment trials of various malignant tumors and has helped in improving the efficacy of immunotherapy. Identifying the most suitable targets for different target mechanisms, while improving the targeting of treatment by improving treatment regimens and reduce the side effects, so as to challenge the huge problems of postoperative recurrence and metastasis is vital. 
Immunotherapy treats a wide range of cancers and is an effective treatment option to cure cancer Many clinical trials are ongoing to find new ways to absorb the body’s immune system to fight cancer. The path of immunotherapy faces great challenges as well as opportunities and will also mature over time.