Cancer Biologic Therapy Definition
Cancer biologic therapy is a type of treatment that uses substances made from living organisms to treat disease, including genetically engineered versions of naturally occurring substances or novel compounds that act directly on the immune system to produce antitumor effects. 1
Core Definition and Scope
Biologic therapy encompasses a diverse group of agents that work through natural host immune mechanisms or the administration of natural biological substances. 2 These treatments are sometimes referred to as "targeted therapy" and include:
- Cytokines - naturally occurring immune system proteins 3
- Monoclonal antibodies - laboratory-made proteins that can bind to specific targets on cancer cells 3
- Immunomodulatory agents - substances that modify immune responses 1
- Genetically engineered biologics - modified versions of naturally occurring substances 3
Mechanism of Action
Biologic therapies produce antitumor effects through several pathways:
- Direct immune system activation - stimulating or restoring the immune system's ability to fight cancer 1
- Targeted cellular mechanisms - acting on specific molecular targets while reducing effects on normal tissue 4
- Immune response modulation - enhancing, suppressing, or modifying immune function depending on therapeutic goals 1
Clinical Context and Application
Biologic therapy represents the fourth modality of cancer treatment alongside surgery, radiation therapy, and chemotherapy. 5, 2 Key characteristics include:
- Natural origin - many biologicals are physiologic mediators of immune response or substances active in growth and maturation regulation 5
- Reduced toxicity profile - as natural mediators, biologicals often have less inherent toxicity than traditional chemotherapy drugs 5
- Targeted approach - these agents can target cancerous cells while minimizing damage to normal tissue 4
Important Clinical Distinctions
The term "biological therapy" falls under the broader category of immunomodulation, which encompasses all therapeutic interventions aimed at modifying the immune response. 1 This differs from:
- Immunotherapy - specifically refers to treatment that stimulates or restores immune system function, commonly used in allergy treatment contexts 1
- Chemotherapy - uses synthetic chemical compounds rather than biologically-derived substances
Examples in Current Practice
Modern biologic therapies approved for cancer treatment include:
- Rituximab - a monoclonal antibody used for various lymphomas and leukemias 6
- Checkpoint inhibitors - blocking CTLA-4 and PD-1 pathways 1
- CAR-T cell therapy - adoptive cellular therapies 1
- Biosimilars - highly similar biologic products with no clinically meaningful differences from existing biologic therapies 1
Clinical Considerations
Biologic therapy requires specialized expertise in immunological and molecular biological applications, distinct from traditional chemotherapy administration. 5 These agents work as physiologic mediators and often involve complex immune system interactions that necessitate specific monitoring and management approaches. 3
The field continues to evolve with combination strategies, including biologics with oncolytic viruses, cancer vaccines, or other immunotherapies, showing promise in improving treatment outcomes. 4