Biological Therapy Agents

Biological therapy involves the use of biologically derived agents to modify the relationship between tumor and host, altering the host's biologic response to tumor cells, with a resultant therapeutic effect. Most biological therapies are designed to activate the patient's immune system and induce it to attack cancer cells. Common biological agents that have been approved for use in treating specific types of cancer are described below.


Interferons are proteins secreted by immune cells that interfere with a virus' ability to reproduce and proliferate. The human body produces interferons as part of the immune response. The name comes from the fact that they literally interfere with virus replication.

Through recombinant DNA technology, various interferons have been genetically engineered for use in the medical treatment of disease. These agents increase the cell-killing activity of the immune system, making tumor cells more vulnerable to immune attack by increasing antigens and blocking the formation of new blood vessels by tumors. They also slow tumor cell replication by inhibiting DNA and protein synthesis.

There are three known classes of interferons: alpha-, beta-, and gamma-interferons. Only alpha-interferon has been approved as a cancer treatment. For example, inteferon alfa-2b (Intron A) is used in conjunction with chemotherapy in patients with follicular lymphoma and has proven to be effective for treating malignant melanoma.

Monoclonal Antibodies (MABs)

Monoclonal antibodies are lab-engineered products. They are components of the immune system which are able to recognize and bind to a specific antigen. These lab-made antibodies are designed to react directly against certain tumor-associated proteins. They may be used by themselves or equipped with other molecules, such as toxins, chemotherapy drugs, or radioactive isotopes.

There are many monoclonal antibodies available for routine use for various types of cancer. The early results of treatment with these therapeutic monoclonal antibodies have been quite promising. Sometimes they have been given on their own, but more commonly in combination with conventional chemotherapy.

Targeted Therapy

Some monoclonal antibodies/therapeutic antibodies are considered to be targeted therapies because they do not cause a response from the immune system. They act by

  • Marking cancers cells so they are more visible and can be killed by the immune system
  • Directly stopping cancer cells from growing
  • Causing cancer cells to self-destruct
  • Serving as a vehicle to carry toxins to cancer cells

Besides monoclonal antibodies, small molecule-drugs are considered a targeted therapy. These drugs can easily enter the cancer cell because of their small size and targets areas inside the cell.

Monoclonal antibodies are used in the treatment of many cancers. For example

  • Atezolizumab (Tecentriq) is used to treat advanced stage and metastatic, breast, small cell lung, non-small cell lung and urothelial cancer.
  • Bevacizumab (Avastin, Mvasi) is used alone or in combination to treat cervical, colorectal, ovarian epithelial, fallopian tube, primary peritoneal, and non-squamous non-small cell lung cancer as well as Glioblastoma and renal cell carcinoma.
  • Cetuximab is used alone or in combination with radiation or chemotherapy to treat head and neck squamous cell carcinoma, colorectal cancer and non-small cell lung cancer.
  • Daratumumab is used alone or in combination to treat multiple myeloma.
  • Ramucirumab is used alone or in combination to treat stomach, gastroesophageal junction adenocarcinoma, and hepatocellular carcinoma.


Interleukin (abbreviated IL) is a group of bioactive proteins produced by leukocytes, monocytes, and other cells that regulate the immune response. They act like messengers between the white blood cells of the immune system. Interleukin-2 increases the activity of lymphocytes, especially killer T-cells. Recombinant IL-2 is used for cancer therapy and continues to be studied as a biological therapy agent for other diseases.

Growth factors are colony stimulating factors or hematopoietic growth factors. These substances promote the growth and maturation of normal cells. There are two types used in cancer treatment: one type stimulates bone marrow to make normal cells; the other acts as an anticancer agent. Colony stimulating factors are being used increasingly in the treatment of bone marrow transplant patients. They are also used for patients who develop anemia or low white blood cell counts because of cancer or cancer therapy.

Tumor Vaccines

Vaccines against viral disease are effective in preventing human infections. They are administered to prevent infections for which effective treatments are not available, especially when active infection is associated with high mortality.

Tumor vaccines are a type of immunotherapy that attempt to stimulate the patient's own immune system to respond to tumor antigens. Melanoma vaccines have been administered to patients for several decades in hopes of boosting immunity to the patient's melanoma, usually as an adjuvant to surgery. Tumor vaccines are still in the early clinical trial phase.

With further research and more secrets about the immune system revealed, the prospect of biological therapies looks promising and hopefully the role of biological therapies in the successful treatment of cancer will grow in future years.

It can be very difficult for registrars to discern which class a drug falls in, therefore SEER Rx Interactive Antineoplastic Drugs Database is used to identify the type of agent class when there is uncertainty about whether a drug is chemotherapy, biologic therapy, or immunotherapy etc.

Updated: December 21, 2023