What Is Biological Therapy for Cancer?

Biological therapy for cancer is a treatment that is made with substances from living organisms. These substances can help the immune system fight cancer cells in the body. Some forms of biological therapy attack specific cancer cells. Biological therapy can also be used to improve side effects caused by other cancer treatments. 

Biological therapy for cancer includes immunotherapy and other targeted therapies. It tends to be better tolerated than other cancer treatments like chemotherapy and radiation therapy. This article will discuss what biological therapy is and the different types of treatments available. 

Doctor Giving IV Treatment to Patient

FatCamera / Getty Images

How It Works

Biological therapy works by either attacking cancer cells directly or by stimulating the immune system to attack cancer cells.

The immune system naturally attempts to attack cancer cells when they start to grow. The problem is that cancer cells have several ways of avoiding immune cells, allowing them to spread rapidly. Cancer cells can evade the immune system by changing their genetic makeup and making themselves less visible. They may also suppress the immune system’s response. 

Some forms of biological therapies stimulate the immune system to target cancer cells with vaccines or bacteria. Biological therapies that boost the immune system’s response are known as immunotherapies

Other forms of biological therapies target cancer cells directly by using segments of genetic material, such as DNA or RNA, or antibodies. There are several forms of biological therapies that have been approved by the U.S. Food and Drug Administration (FDA) and many more are being researched.


Biological therapy works with the body’s immune system to attack cancer cells. It does this by boosting the immune system’s response or by targeting cancer cells directly. 


Several types of biological therapies are used to treat cancer, including:

  • Bacillus Calmette-Guerin (BCG): This is the first biological therapy created to treat cancer and to be approved by the FDA. BCG is a weakened form of live tuberculosis bacterium that can be used to treat bladder cancer. The weakened bacterium does not cause disease, and when it is administered into the bladder, it stimulates the immune response. 
  • Oncolytic viruses: These viruses can be injected into the blood. They do not appear to have any effect on healthy cells but can kill cancer cells. 
  • Cytokines: Cytokines are proteins made by white blood cells. They help control the immune system’s response to disease, and can be used to boost its response against cancer cells. 
  • Immune checkpoint inhibitors: This therapy works by blocking the checkpoints on immune system cells. These checkpoints normally keep the immune system in check and prevent it from responding too strongly. Immune checkpoint inhibitors block the checkpoints so that the immune system increases its response to cancer cells. 
  • T-cell transfer therapy: T-cells are white blood cells that are part of the immune system. T-cell transfer therapy involves taking immune cells from the cancerous tumor, then changing them in the lab to attack your specific type of cancer. These cells are then re-administered through an intravenous (IV) needle into the vein. 
  • Monoclonal antibodies: These antibodies are immune system proteins that are grown in a lab and can bind to certain targets on cancer cells. Monoclonal antibodies essentially make the cancer cells more visible to the immune cells. 
  • Cancer vaccines: Cancer treatment vaccines do not prevent disease but can help treat cancer. They work by boosting the immune system’s response to cancer cells. 
  • Immune system modulators: Immune system modulators can boost the immune system’s response against cancer cells. 


Biological therapies are used in cancer treatment to fight cancer cells and relieve side effects from other treatments like chemotherapy. Cancers that have been treated effectively with biological therapies include:

Biological therapies have also been used for other conditions, including:

How to Prepare

As with any cancer treatment, your biological therapy will depend on the type of cancer you have, how advanced it is, and how well your body tolerates the treatment. Biological therapy is usually administered in a doctor’s office or outpatient clinic. 

The treatment schedule will depend on the type of biological therapy used. Your medical team may recommend treatments every day, week, or month. Some types of biological therapy are administered in cycles. This refers to a period of treatments, followed by a period of rest. The rest time allows your body to recover from treatment and start making healthy cells. 

Biological therapies can be administered in the following forms:

  • Topical: The treatment is applied to the skin as a cream or ointment.
  • Oral: The treatment is administered by mouth as a pill or capsule.
  • Intravenous (IV): The treatment is administered directly into the vein.
  • Intravesical: The treatment is administered directly into the bladder.


Talk with your physician about how best to prepare for your biological therapy. Most types are administered in the doctor’s office and may follow a daily, weekly, or monthly schedule. 


During the course of biological therapy, you will have frequent follow-up appointments with your physician and medical team. At the follow-up appointments, your doctor will perform a physical exam, ask about any side effects, and order tests to check the status of your cancer. These tests may include blood tests or imaging studies to determine the size of the tumor. 


While biological therapy typically causes fewer side effects and complications than other types of cancer treatment, it can still lead to adverse effects.

Biological therapy may cause side effects in some people. The side effects usually occur at the injection site. Other side effects may feel like flu symptoms. This is due to the immune system being activated. It’s also possible that biological therapy may not be effective for your type of cancer. 

Possible side effects include:

  • Pain, swelling, or a rash at the injection site
  • Fever
  • Chills
  • Nausea and vomiting
  • Diarrhea 
  • Muscle aches
  • Headache
  • Fatigue
  • Fluid retention
  • Low blood pressure (hypotension)
  • High blood pressure (hypertension)
  • Difficulty breathing


Biological therapy for cancer treatment uses living organisms to boost the immune system’s response to cancer cells or by attacking cancer cells directly. Examples of biological therapies include oncolytic viruses, cytokines, immune checkpoint inhibitors, T-cell transfer therapy, monoclonal antibodies, treatment vaccines, and immune system modulators. 

Biological therapy usually causes fewer side effects than other types of cancer treatment like chemotherapy or radiation therapy. Possible side effects include an injection site reaction or flu-like symptoms. 

A Word From Verywell

Navigating your cancer treatment plan is often an overwhelming process. It’s helpful to remember that cancer treatments are always evolving and improving. Consider talking with your doctor about biological therapies and which one may benefit you. 

Frequently Asked Questions

  • What is the difference between chemotherapy and biological therapy?

    Chemotherapy and biological therapy are both cancer treatments used to fight cancer cells. Chemotherapy uses chemicals to do this, and biological therapy uses substances from living organisms. Chemotherapy kills cancer cells directly, and biological therapy either attacks cancer cells directly or stimulates the immune system to attack cancer cells. 

  • What is the difference between biological therapy and immunotherapy?

    Immunotherapy is a type of biological treatment that helps your immune system fight cancer cells. Immunotherapy includes treatments that boost the immune system's response to cancer cells. Biological therapy includes immunotherapy and other targeted therapies. 

  • How effective is biological therapy for cancer?

    Biological therapy is always evolving and being studied so the treatment will continue to improve over time. Studies have found that BCG, the first approved biological therapy, is more effective and causes fewer side effects than chemotherapy. 

9 Sources
Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
  1. National Cancer Institute. Definition of biological therapy

  2. Schirrmacher V. From chemotherapy to biological therapy: a review of novel concepts to reduce the side effects of systemic cancer treatment (review). Int J Oncol. 2019;54(2):407-419. doi:10.3892/ijo.2018.4661

  3. Oncology Nurse Advisor. Biological therapies for cancer (fact sheet).

  4. Dana-Farber Cancer Institute. Biological therapy and chemotherapy: what are the differences?

  5. National Cancer Institute. Immunotherapy for cancer.

  6. Yang Y. Cancer immunotherapy: harnessing the immune system to battle cancer. J Clin Invest. 2015;125(9):3335-3337. doi:10.1172/JCI83871

  7. Hegde PS, Chen DS. Top 10 challenges in cancer immunotherapy. Immunity. 2020;52(1):17-35. doi:10.1016/j.immuni.2019.12.011

  8. National Cancer Institute. Side effects of immunotherapy.

  9. American Cancer Society. Intravesical therapy for bladder cancer.

By Carrie Madormo, RN, MPH
Carrie Madormo, RN, MPH, is a health writer with over a decade of experience working as a registered nurse. She has practiced in a variety of settings including pediatrics, oncology, chronic pain, and public health.