A Brief History
Immunotherapies (biologics/cell therapies/vaccines) are among the most promising treatments in current pharmaceutical development.
What is an immunotherapy? The text book definition is the "treatment of disease by inducing, enhancing, or suppressing an immune response." Originally, the term comprised the therapeutic administration of serum or immune globulin containing preformed antibodies produced by another individual. Immunotherapy includes nonspecific systemic stimulation, active specific immunotherapy, allergen immunotherapy and adoptive immunotherapy. New forms of immunotherapy, specifically for cancer treatment, include the use of monoclonal antibodies (MAbs). Cancer immunotherapy attempts to stimulate the immune system to reject and destroy tumors.
Immuno cell therapy for cancer was first presented in the late 1980s by Rosenberg and his team at the United States, National Institutes of Health. Rosenberg reported a clinical trial in 1,205 patients with metastatic cancer who underwent different types of active specific immunotherapy. The immunotherapy regimes produced low tumor regression rates (2.6–3.3%). Rosenberg and his team thereby concluded that immuno cell therapy along with specific chemotherapy was the future of cancer immunotherapy.
The adverse effects of these initial immunotherapy products, largely cytokines such as Interleukin, sparked new techniques involving the extraction of lymphocytes from the blood and expansion in vitro against specific tumor antigens, before then injecting the cells into patients with the appropriate stimulatory (immunomodulatory, see below)) cytokines. These newly engineered cells then specifically target and destroy the tumor expressing antigen against which they have been raised.
Cell-based or adoptive immunotherapies are proven to be effective for some cancers. Immune effector cells such as lymphocytes, macrophages, dendritic cells, natural killer cells (NK Cell), cytotoxic T lymphocytes (CTL), etc, work together to defend the body against cancer by targeting abnormal antigens expressed on the surface of the tumor due to mutation.
Another promising specific and cell based immunotherapy involves the use of “loaded” specific antibodies for different types of tumor cells. These antigen specific antibodies contain either anti-neoplastic drugs or radioactive materials. When injected into the bloodstream of a patient with that particular kind of tumor, these “loaded” antibodies attach to the surface of the malignant tumor cells, thereby specifically targeting these cells and causing less damage to healthy non-malignant cells.
Non-specific immunotherapy relies on general immune stimulants to activate the whole immune system rather than specific tumor cells. In the past decade, immunotherapy against cancer has involved the use of the bacille Calmette-Guérin vaccine (bcg vaccine), which is evolved from strains of Mycobacterium tuberculosis, and is used to provide some immunity to tuberculosis.