Immunotherapy in cancer treatment

The use of immunotherapy in cancer treatment was first introduced in 1891 by Dr. William B Coley who attempted to creatively harness patients’ immune system by injecting mixtures of live and attenuated bacteria into their tumours. Dr. Coley achieved durable complete remission in several types of malignancies including sarcoma, lymphoma, and testicular carcinoma. 

The idea re-emerged in 1957 when Lewis Thomas and Sir Frank Macfarlane Burnet first proposed their theory of cancer immunosurveillance. They postulated that lymphocytes acted as sentinels to identify and eliminate somatic cells that were transformed by spontaneous mutations.

Today, scientists continue to experiment with and learn about immunotherapies including the following: 

• T Cell Research: The use of antibodies to block the action of CTLA-4, which acts as a ‘brake’ on T cell activation. Release of this brake enables a powerful immune response to the tumour cells.
• Adoptive Cell Therapy: For chimeric antigen receptor (CAR)-T therapies, a patient’s T cells are isolated and then engineered to express a CAR on its surface. The receptor enables the T cells to identify and destroy cancer cells that express a specific target molecule.
• Viral vectors: These are used to introduce genes into mature T cells to generate immunity to cancer through the delivery of CARs and/or cloned T cell receptors, however long-term follow-up studies are required due to the risk of patients developing secondary malignancies.
• Tumour Mutation Burden (TMB): Data suggests that TMB is an independent predictor for patient stratification and response to immunotherapies, such as checkpoint inhibitors.
• Tumour infiltrating lymphocytes (TILs): Recent evidence has emerged that TILs present in some cancers prior to treatment can predict response to therapy and improved prognosis.

Immunotherapy has been the focus of medical research for many years, but as scientists continue to experiment with and learn about the form of therapy, it is becoming apparent we may not have even scratched the surface of its potential in the treatment of cancer.

For more information on this topic or to speak with one of ICON's oncology experts, please contact us.

This blog is an edited version of “Leveraging Novel Therapeutics and Diagnostic Assays” which appeared in the July 2019 edition of ebr Magazine. To view the full article, please visit http://www.samedanltd.com/.