Modern immunotherapy

Immunotherapies aim to improve the immune response to a cancer that a patient’s immune system had previously failed to target.

Novel immunotherapies are designed to further activate the patient’s own immune system.

Main categories include:

• Monoclonal antibodies
• Vaccines
• CAR-T cells
• Cytokines
   

Other novel immunotherapies, so-called checkpoint inhibitors, block biological mechanisms that cancers use to prevent an immune response.  

The following Nature Cancer Immunotherapy animation provides an overview of immunotherapies (including bacterial immunotherapy and references to Coley's toxins and BCG). 

Limitations of modern immunotherapy
Modern immunotherapies are often based on defined targets.

For instance monoclonal antibodies, CAR-T cells and vaccines are not based on entirely cancer specific molecules. Their clinical effect thus depends on the presence of this molecule in a patient’s to be treated tumour whereas side effects will depend on their abundance on healthy cells (that immunotherapies can but should not target). Both the efficacy and side effects of these therapies will therefore vary per individual patient and all will not be effective against tumour cells that do not express the targeted molecule. 

Cytokines help activate the immune system and checkpoint inhibitors block molecules that cancer cells express to avoid an immune response. Both therefore rely on the effect of these individual molecules and will only meaningfully activate the immune response if they act on what happens to be the weakest link in the complex immune system machinery of the to be treated patient.