Clinical Considerations for Immunotherapy

Immune Response


Immunotherapy treatment activates T cells and B cells that target specific tumor antigens

  • The activated immune system is primed to recognize tumor antigens expressed by each patient's unique and frequently changing population of cancer cells
  • Some activated T cells kill tumor cells directly or indirectly
  • Some activated T cells activate B cells, which become antibody-producing plasma cells

Immunotherapy treatment is designed to support the immune system's ability to adapt its attack over time

  • Each patient's population of tumor cells mutates over time, which may result in resistance to traditional anticancer therapies
  • When a tumor cell is killed, additional antigens are released, stimulating activation of new populations of T cells and B cells that recognize tumor antigens
  • This can result in an expanding cascade of immune cells able to recognize cancer cells bearing a variety of tumor antigens as the tumor mutates over time

Immunotherapy treatment stimulates immunologic memory, which may lead to a prolonged antitumor response

  • Some activated immune cells become memory cells, which remain primed to stimulate an immune response when tumor cells bearing target antigens are encountered within the body
Immunotherapy is Different From Chemotherapy

Patients may respond differently to immunotherapy than to traditional cancer agents.

  • Immunotherapy targets the tumor over time, so although response may occur more slowly than with traditional cytotoxic therapies, the immune effect is potentially adaptable and durable
  • RECIST criteria were designed to assess response to traditional cytotoxic agents so they are not as relevant for immunotherapy, which works differently
Patients may respond differently to immunotherapy than to traditional cancer agents.

It has been suggested that the relative efficacy of immunotherapy may be greater with a smaller tumor burden.

Immunotherapy has Potential for Synergy

Since immunotherapy offers a different mechanistic approach than traditional therapies, there is potential for synergy with traditional therapies, such as chemotherapy and radiation. Several monoclonal antibodies that bind to specific targets on cancer cells when added to chemotherapy have been shown to improve survival, compared with chemotherapy alone.