Biological Therapy Drugs

Biological Therapy Drugs

Also called: Biological Agents, Biological Response Modifiers, Biological Drugs, BRMs

Reviewed By:
Martin E. Liebling, M.D., FACP

Summary

Biological therapy is a form of treatment that uses the body’s own immune system to fight cancer.  This type of cancer treatment can work either directly or indirectly to enhance, repair or stimulate the immune system’s response to cancer. There are also certain types of biological therapy that may be used to reduce the side effects of cancer treatments such as chemotherapy.

Biological therapy uses specific drugs, known as biological response modifiers (BRMs).  Each BRM works differently with the body to fight the cancer or improve the health of the patient undergoing cancer treatment. These drugs are substances found in the immune system, such as antibodies and cytokines, but they are produced in a laboratory when they function as BRMs. 

The BRMs used in biological therapy include:

  • Interferons (IFNs). Interferons are part of the immune system that belong to a class of substances called cytokines. Interferons are usually associated with viral infections, although they are also produced in response to bacteria and other foreign invaders.

  • Interleukins (ILs). Interleukins are also cytokines. These chemicals are produced by a variety of cells in the immune system to regulate and mediate the white blood cells. In cancer treatment, interleukins are used experimentally to destroy cancer cells.

  • Monoclonal antibodies (MOABs). Natural antibodies are proteins that fights off infections. Monoclonal antibodies are created artificially and can be targeted against specific areas of cancer cells. MOABs help the body recognize cancer cells so they can be destroyed by the immune system.

  • Colony-stimulating factors (CSFs). Sometimes called hematopoietic growth factors, these drugs stimulate bone marrow stem cells to divide and develop into white blood cells, red blood cells and platelets. Cancer treatments such as chemotherapy can lower the counts of these blood cells. CSFs can help replace the cells.

  • Nonspecific immunomodulating agents. Substances that stimulate and indirectly augment the immune system.

  • Anti-angiogenesis substances or vascular endothelial growth factor (VEGF) inhibitors.A new biological therapy that shows promise in fighting cancer. This strategy prevents tumors from generating new, small blood vessels necessary for the tumor to sustain itself.

  • Gene therapy. This treatment is based on altering a cell’s genetic material to fight or prevent disease. IGene therapy is still experimental in cancer treatment, Researchers are using gene therapy to sensitize the immune system to kill cancer cells, make cancer cells more sensitive to chemotherapy and deliver special drugs on genetic material.

  • Cancer vaccines. Researchers are developing vaccines that either prevent the development of cancer or treat existing cancers by helping the patient’s body to recognize and fight cancer, and keep it from recurring.

  • Epithelial growth factor receptor (EGFR) inhibitors. EGFR has been associated with aggressive cancer cell growth in tumors. EGFR inhibitors are drugs that may help prevent the development and progression of cancer in certain tumors.

Biological therapy drugs are administered in various ways, depending on the type of treatment. Oral and some injection treatments may be taken at home, while intravenous administration may require visits to a clinic or hospital. Treatment doses and schedules vary and can range from daily to once every few months.

The medications may be taken alone or in combination with other treatments, such as chemotherapy or radiation.  Many of the therapies may be available only through clinical trials. A patient’s medical oncologist can best determine if biological therapy is a viable treatment option.

As with other cancer treatments, biological therapy can cause side effects. The most common side effects include rashes or swelling at the injection site and flu-like symptoms.

About biological therapy drugs

Biological therapy uses drugs known as biological response modifiers (BRMs) to treat cancer. These drugs act in a number of ways to provoke a strong immune-system response or restore immune function. They are used in the treatment of a number of diseases, including cancer. In cancer treatment, BRMs are used to both help the body identify and destroy cancer cells and to reduce the side effects of chemotherapy.

Other BRMs work directly on the cancer cells rather than with the immune system. These agents can slow the growth of the cells or promote their development into more normal behavior. In addition, some BRMs are used to help combat damage in the body that can occur with cancer treatments, such as chemotherapy.

Biological therapy drugs have three major effects on the immune system:

  • Repair. Drugs such as colony-stimulating factors help restore levels of red blood cells, white blood cells and platelets that are sometimes damaged during chemotherapy and radiation therapy. These cells are important to the body’s well-being.

  • Stimulate. Drugs such as interferons, monoclonal antibodies and cancer vaccines help the immune system to recognize and attack cancer cells. They also can work directly against cancer cells and interfere with their growth and development.

  • Enhance. Drugs such as interleukins can boost the production and the activity of certain white blood cells, giving the immune system greater power in attacking cancer cells.

Biological therapy drugs may be the sole means of treating a patient’s cancer, or may be used in combination with other treatments.

Types and differences of drugs

Biological therapy approaches vary, but all try to help the immune system recognize cancer cells as foreign invaders. The various drugs used in these treatments are known as biological response modifiers (BRMs). They include:

  • Interferons (IFNs). A drug that mimics a type of cytokine, a protein that activates certain immune system cells and is made by the body. The three types of interferon are interferon alpha, interferon beta and interferon gamma. Interferon alpha is the type most commonly used in cancer treatment. These medications boost interferon levels to slow the growth of cancer cells and stimulate the immune system to fight cancer cells. They also help promote the transition of cancer cells into cells that behave more normally. Some interferons may boost the immune system’s anticancer function by stimulating various immune system cells such as NK cells, T cells and macrophages.

    Interferon alpha was the first cytokine known to have an antitumor effect. Researchers are testing the anticancer effects of interferon beta and interferon gamma. All the interferons are being studied for effectiveness when combined with other cytokines and chemotherapy. 

Interferons are being used to treat the following:

  • Leukemia
  • Melanoma
  • Kaposi’s sarcoma
  • Kidney cancer Non-Hodgkin’s lymphoma

Interleukins (ILs). As with interferons, these drugs are produced in a laboratory to mimic a cytokine made naturally by the body. While more than a dozen interleukins have been developed, only interleukin-2 (IL-2) has been approved by the U.S. Food and Drug Administration (FDA) for treatment of cancer. IL-2 helps boost production and stimulate certain white blood cells, especially T cells. This gives the immune system more power in identifying and attacking cancer cells. Other interleukins are being studied in clinical trials.

Some researchers are experimenting with IL-2 by removing T cells from a patient’s body, creating additional T cells in a laboratory and stimulating them with IL-2. The cells then are returned to the body in greater numbers than the human body can produce on its own. Early results have shown promise. 

Interleukins are used to treat the following:

  • Melanoma
  • Leukemia
  • Lymphoma
  • Brain cancer
  • Breast cancer
  • Ovarian cancer
  • Men’s reproductive cancers
  • Colorectal cancer

Monoclonal antibodies (MOABs). An artificial antibody (protein that fights infections) that can be targeted against specific areas of cancer cells. The MOABs are injected into the body, where they attach to the area for which they were made, most often on the surface of certain cancer cells. When this occurs, it helps the body recognize the cancer cells as foreign, triggering the immune system to detect and attack the cells. In addition, MOABs can act directly against cancer cells and interfere with their growth and development.

To create these drugs, scientists first inject human cancer cells into mice. When the mice make antibodies to these cells, the mouse plasma cells that produce the antibodies are removed and fused with laboratory–grown cells. This creates hybrid cells called hybridomas, which produce large quantities of monoclonal antibodies.

MOABs may be used to treat cancer in the following ways:

  • Enhance a patient’s immune response to a specific cancer

  • Interfere with the growth of cancer cells

  • Binding and delivering radioactive substances, anticancer drugs and toxins directly to tumor cells to help with destruction 
  • Enhance a patient’s immune response to a specific cancer

  • Interfere with the growth of cancer cells

  • Binding and delivering radioactive substances, anticancer drugs and toxins directly to tumor cells to help with destruction 

However, monoclonal antibodies can only travel a few cell layers deep from where blood vessels enter a tumor. As a result, they do not kill cancer cells that are distant from a blood vessel. Clinical research continues on methods to improve the cancer–fighting effectiveness of monoclonal antibodies.

Examples of MOABs include:

  • Rituxan (most often used in lymphomas)
  • Herceptin (shown to be effective in both treating and preventing recurrences of breast cancer)

Other monoclonal antibodies are being studied to treat the following:

  • Non-Hodgkin’s lymphoma
  • Acute myelogenous leukemia
  • Chronic lymphocytic leukemia (CLL)
  • Breast cancer
  • Colorectal cancer
  • Lymphoma
  • Leukemia
  • Melanoma
  • Brain cancer
  • Lung cancer
  • Kidney cancer
  • Reproductive cancers


Colony-stimulating factors (CSFs). Sometimes called hematopoietic growth factors, these drugs stimulate bone marrow stem cells to divide and develop into white blood cells, red blood cells and platelets. Bone marrow is important to the immune system because it is the source of all blood cells. It is often damaged in treatments such as radiation therapy and chemotherapy, decreasing the effectiveness of the immune system. Thus, the ability of CSFs to stimulate the production of these cells may allow physicians to increase the dose of anticancer drugs without the risk of infection or need for blood transfusions. Filgrastim and erythropoietin are examples of hematopoietic growth factors.

Colony-stimulating factors are currently being used in treating most cancers, including: 

  • Lymphoma
  • Leukemia
  • Multiple myeloma
  • Melanoma
  • Brain cancer
  • Lung cancer
  • Esophageal cancer
  • Breast cancer
  • Reproductive cancers
  • Kidney cancer
  • Colorectal cancer

Nonspecific immunomodulating agents. Substances that stimulate and indirectly augment the immune system. These agents act directly on immune system cells and cause secondary responses such as increased cytokine and antibody production. For example, Bacillus Calmette Guerin (BCG) is a vaccine for tuberculosis that is also used to treat some forms of bladder cancer and colorectal cancer.

Antiangiogenesis is a new biological therapy that shows promise in fighting cancer. This strategy prevents tumors from generating new, small blood vessels necessary for the tumor to sustain itself. Several chemicals and antibodies have shown the ability to block angiogenesis, making it possible to shrink the tumor. An antiangiogenesis therapy that has shown results treating multiple myeloma is thalidomide, which was banned in the early 1960s after it cause devastating birth defects in the infants of pregnant women who took the drug. Its current use is strictly regulated. Newer, related antiangiogenic medications have also been developed.

Epithelial growth factor receptor (EGFR) inhibitors. EGFR has been associated with aggressive cancer cell growth in tumors. EGFR inhibitors are drugs that may help prevent the development and progression of cancer in certain tumors. Recent research has shown that the EGFR inhibitor lapatinib may improve survival rates in patients with advanced breast cancer, when it is combined with chemotherapy. Other studies of lapatinib to treat kidney cancer have produced mixed results.

Gene therapy. This treatment is based on altering a cell’s genetic material to fight or prevent disease. It is an experimental method that involves introducing genetic material, such as DNA, into an individual’s cells to fight cancer. Some approaches of gene therapy target the destruction of cancer cells to prevent their growth. Other forms of gene therapy focus on increasing the ability of healthy cells to fight cancer. Gene therapy is currently available only in clinical trials.

There are several techniques being studied with gene therapy. Researchers are evaluating the replacement of missing or altered genes with healthy genes. In another approach, researchers are injecting cancer cells with genes that can be used to destroy the cells or genes that can make the cells more sensitive to chemotherapy and radiation therapy. Scientists continue to study additional uses of gene therapy in cancer treatment.   Cancer vaccines. Vaccines are medications that expose the body’s immune cells to weakened forms of antigens associated with various diseases. This exposure to the antigens present on the surface of the foreign cells causes the immune system to increase the production of antibodies and T cells to fight them.

Some cancer vaccines consist of cancer cells that have been inactivated (usually through radiation) before being injected into the body. While these cells no longer can grow, they still retain the signals that trigger the immune system to attack cancer in the body. The cells can come from the patient’s own cancer or from the patient’s immune system. In the latter case, the cells are manipulated to recognize cancer before being injected back into the body. Once inside the body, these cells begin to attack cancer cells and signal other immune system cells to do the same.  

Researchers are studying vaccines to treat existing cancers or to prevent healthy individuals from developing cancers.  Early cancer vaccine trials are being used with many types of cancer, including men’s and women’s reproductive cancers. In 2006, the U.S. Food and Drug Administration approved a vaccine that protects against four types of human papillomavirus, which cause most cases of genital warts and cervical cancer. Vaccines have also shown promise for cancers of the breast, lung, kidney and liver.

Potential side effects of biological therapy

While biological therapy drugs have shown great benefits in treating some cancers, they may also cause side effects. These may include:

  • Rashes or swelling at an injection site
  • Flu–like symptoms, including fever, chills, nausea, vomiting, diarrhea, loss of appetite, fatigue, bone pain and muscle aches
  • Low blood pressure
  • Allergic reactions

Patients who experience any of these side effects should consult a physician.

The types and frequency of side effects associated with biological therapy drugs varies between drug classes and can include:

  • Interferons:
    • Decreased appetite
    • Seizures
    • Changes in taste, and dry mouth or throat
    • Partial hair loss
    • Impotence
    • Menstrual irregularities
  • Interleukins:
    • Decreased red blood cell count (anemia)
    • Decreased urine output
    • Mouth or lip sores
    • Impaired memory
    • Difficulty talking
    • Fluid in the lungs
    • Peeling of skin on hands and feet
  • Monoclonal antibodies:
    • Swelling of the tongue or throat
    • Generalized pain
    • Abdominal or bone pain
    • Cough with shortness of breath
  • Colony-stimulating factors:
    • Swelling of feet
    • Weight gain
    • Bone pain

Patients who are receiving biological therapy and experience these symptoms should promptly advise their physicians.

Pregnancy use issues

Some biological therapy drugs can cause birth defects in the children of women who are pregnant. With some medications, there is a risk that men using biological therapy drugs who plan to become fathers could also contribute to birth defects. Therefore, patients who are considering becoming parents should consult with their physician if they are currently pregnant or plan to become pregnant.

Questions for your doctor

Preparing questions in advance can help patients have more meaningful discussions with their physicians regarding their conditions. Patients may wish to ask their doctor the following questions about biological therapy drugs:

  1. Am I a candidate for biological therapy?
  2. What type of drug would be used in my treatment?
  3. What are the benefits and risks of the drug?
  4. How effective is the biological drug for my type of cancer?
  5. What side effects are associated with the drug?
  6. Am I a candidate for a clinical trial for biological therapy?
  7. How will I receive the biological therapy drug and on what schedule?
  8. How will I know if the drug is successful in treating my cancer?
  9. If the first drug does not work, will you try another type?
  10. What is my prognosis with and without this type of  biological therapy?
  11. Will biological therapy be used in conjunction with other treatments?
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