What Are Biologic Treatments?

Differences between Biologic Treatments and Traditional Pharmaceutical Drugs

"Biologics" refer to any type of medical therapy that is derived from living organisms such as humans, animals, or microorganisms. This contrasts with traditional non-biologic pharmaceutical drugs, which are synthesized in a laboratory via chemical processes without using parts of living things. Other terms also sometimes used include “biologic therapy,” “biological therapy,” “biologicals,” and “biopharmaceuticals.” You might also hear them called by their over-the-counter names, or as a specific subcategory of biologic therapies (e.g., gene therapy).

The oldest forms of biologics have been around for many years, such as the vaccines developed in the 19th century. Insulin was another relatively early biologic therapy. However, since the 1990s, the number of biologics on the market has vastly multiplied. Many types of biological therapy are now available to treat a wide array of different medical conditions such as various forms of cancer and autoimmune diseases. More are developed and made available every year. These biologic therapies all come with different benefits and potential risks.

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What Types of Biologic Therapy Are Available?

Some of the general classes of biologics include:

  • Blood or other blood products (like platelets)
  • Steroid hormone therapies (like estrogen, testosterone)
  • Vaccines (such as for disease prevention)
  • Antitoxins (such as to treat a snakebite)
  • Recombinant proteins (such as insulin or erythropoietin)
  • Recombinant nucleic acids (such as those developed for genetic hypercholesterolemia)
  • Interleukins(immune molecules that can be used to treat certain infections and cancers)
  • Tendons, ligaments, or other materials used for transplantation
  • Monoclonal antibodies (like those used to treat autoimmune diseases and cancer)
  • Stem cell therapies (such as for certain cancers or genetic diseases)
  • Other cell therapies (like specific T cells used to treat cancer)
  • Gene therapies (such as those for genetic conditions)

How Do Biologics Work?

Different biologic therapies have different purposes, targets, and design, and they all work a little differently. Don’t hesitate to ask your healthcare provider if you have questions about the particular biologic therapy relevant to you.

As an example, tocilizumab (trade name Actemra), a biologic used to treat rheumatoid arthritis, belongs to a class of biologic therapies called monoclonal antibodies. Technically, tocilizumab is a recombinant monoclonal IgG1 anti-human IL-6 receptor antibody. Unlike antibodies your body makes naturally, this type of antibody doesn’t fight infection. Instead, it can be used to directly target conditions like rheumatoid arthritis.

IL-6 is a cytokine (an immune-signaling molecule). It can bind cells and send signals. When IL-6 binds, it tends to increase inflammation and other processes that worsen rheumatoid arthritis. Tocilizumab partly blocks the receptor for IL-6, which may decrease symptoms.

These particular monoclonal antibodies are produced through a series of steps, beginning with early production of antibodies in mice. Then scientists modify these antibodies, replacing much of them with portions of antibodies from humans. Inside the laboratory, many identical copies of these new antibodies are made. These hybrid antibodies can then be given to the patient to help block the body’s response to IL-6.

If a biologic has “ab” at the end of its name, it is a good clue that the product is some kind of modified antibody.

How are Biologic Therapies Different from Traditional Pharmaceutical Drugs?

In general, the manufacturing process for biologics is more complicated than for small molecule drugs (“non-biologic” drug treatments, such as aspirin). This is part of why biologics are typically more expensive than non-biologic treatment alternatives. Because the manufacturing process is so complicated, the structure of biologics may not be fully understood. It may be difficult or impossible for another company to exactly replicate it.

Biologics are larger, more complex molecules compared to traditional pharmaceutical drugs. Unlike traditional pharmaceuticals, they require some component from a living organism in order to be manufactured.

On the whole, biologic therapies are more target-mediated than nonbiologic treatments. For example, methotrexate and sulfasalazine are two non-biologic drug treatments for rheumatoid arthritis. These drugs affect multiple different parts of a person’s immune system. By contrast, biologic therapies for rheumatoid arthritis have very specific targets (such as blocking a specific receptor for a targeted immune molecule). This decreases the likelihood of certain side effects, although others are still a potential risk.

Biologics tend to be more sensitive to heat and light. Often, they cannot be taken by mouth, but must be given by injection or infusion.

Conditions That Can Be Treated With Biologic Therapy

More recently-developed biologic therapies have revolutionized the treatment of many different diseases. They have been especially important for the treatment of autoimmune diseases, cancer, and certain genetic conditions.

For example, biologic therapies have been developed to treat the following:

  • Rheumatoid arthritis
  • Psoriasis
  • Ankylosing spondylitis
  • Crohn's disease
  • Multiple sclerosis
  • Diabetic retinopathy
  • Age-related macular degeneration
  • Diabetes
  • Gastric cancer
  • Breast cancer
  • Colon cancer
  • Forms of leukemia and lymphoma
  • Infertility
  • Osteoporosis
  • Cystic fibrosis
  • Hemophilia
  • Sickle cell disease

Biologics in Autoimmune Diseases

Some of the most commonly used biologics are used for autoimmune diseases, diseases in which the body’s immune system plays a role in abnormally attacking its own tissue. These include conditions like rheumatoid arthritis, psoriasis, Crohn’s disease, and others. Many of these particular therapies are FDA-approved to treat more than one type of autoimmune disease. In some cases, healthcare providers may prescribe these treatments off-label if they haven’t undergone the full suite of studies needed for FDA-approval, but there is still good reason to think they might be effective.

Because biologics are often expensive and more difficult to administer, they are often (but not always) given after you have tried another non-biologic type of therapy.

One of the most common types of modern biologic therapies for autoimmune disease is the TNF blocker. TNF blockers include the popular drugs etanercept(Enbrel), adalimumab (Humira), and infliximab (Remicade). These drugs all block the downstream inflammatory effects of an immune molecule called TNF-alpha. They are FDA-approved for several different autoimmune diseases.

Other biologics have been developed to block the receptors for different immune molecules. Others were designed to target T cells, specific cells in the immune system. Some of these other biologics important in autoimmune disease include:

  • Ustekinumab (Stelara)
  • Secukinumab (Cosentyx)
  • Abatacept (Orencia)
  • Guselkumab (Tremfya)
  • Skyrizi (risankizumab-rzaa)

Another important biologic in autoimmune disease is interferon beta-1a (Avonex), which is a key treatment for multiple sclerosis.

Biologics in Cancer Treatment

Biologic therapies are also very important for cancer treatment, and many continue to be developed. There are many different types of these treatments. Sometimes they are used as a first-line treatment. Other times they are used after other treatments have failed, or in advanced cancers. Often, they are used in addition to other treatments.

Some of these treatments are therapeutic antibodies. For example, the drug, pembrolizumab (Keytruda) is a biologically-designed antibody that is approved to treat many different types of solid tumors. It works by targeting a particular receptor found on certain immune cells. That allows the immune cells to more easily destroy cancer cells. These types of biologic therapies that stimulate the body’s immune system to better fight cancer are called immunotherapies.

Other types of therapeutic antibodies interfere with signaling pathways that promote tumor growth, such as trastuzumab (Herceptin). Or they may trigger cancer cells to destroy themselves, like rituximab (Rituxan). In other cases, they may be linked to a toxic substance, which can help destroy the cancer cells. For example, the drug ado-trastuzumab emtansine (Kadcyla) works in this fashion. Other types of therapeutic antibodies also exist.

Immune cell therapy is another important area of biologic cancer therapy under development. This involves collecting some of an individual’s immune cells, modifying them in some way, and then reinjecting them. This makes the person’s immune cells better able to attack the tumor. Tumor-infiltrating lymphocyte therapy and CAR-T cell therapy both fall in this category.

Another important class of biologics include proteins made in a laboratory. For example, several different immune molecules (different types of interferons and interleukins) are used for multiple types of cancer.

Biologics in Rare Genetic Diseases

Biologic therapy is also very important in the treatment of rare genetic diseases. This will probably only become more important in the future as more and more genetic therapies become available. For example, some biologic therapies to treat rare diseases include enzyme replacement therapy for Gaucher disease, blood clotting factors for hemophilia, or immunoglobulins for people with certain genetic immune disorders.

Stem cell transplants, used to treat many types of rare genetic diseases, including sickle cell disease, are also a kind of biologic therapy. Researchers are also continuing to develop RNA therapies and gene therapies that might ultimately be used to cure many rare diseases.

Potential Side Effects

Potential side effects of biologics vary based on the specific biologic therapy involved. In some cases, these side effects are quite mild, such as a rash. Some other common side effects might include respiratory infections, flu-like reactions, or redness at the injection site.

However, more serious side effects are also possible, such as a severe allergic reaction. There are some specific potential side effects of biologic therapies that target different parts of the immune system. In particular, many of these treatments come with a risk of immunosuppression. That means that part of your immune system can’t respond to fight off infections the way it normally would. This might make you more susceptible to certain types of infections. In some cases, they might run the risk of reactivating dormant infections that otherwise wouldn’t necessarily give you a problem, such as tuberculosis.

Certain biologic therapies that target the immune system may also increase the risk of certain cancers. However, this is not true of all biological therapies. Also, the risk might be only small or nonexistent in a drug that otherwise gives many potential benefits. Talk things through with your health provider to make sure you make a decision that makes sense for you. Risks are generally better understood for biologic therapies that have been around for a while compared to newer treatments. Your healthcare provider can give you a better idea of the potential side effects of a particular biologic therapy in your situation.

Are Biologics Safe to Use During Pregnancy and Breastfeeding?

Most biologic therapies have not been studied in pregnant or breastfeeding women, but we know that specific biologic treatments may be dangerous for a fetus or a breastfeeding infant. However, it may also be a risk to stop a biologic treatment if you are already using one. Talk to your healthcare provider about your particular situation and the overall risks and benefits. If you are taking a biologic therapy and find out that you are pregnant, don’t stop taking it right away. Instead, call your practitioner’s office and tell them the situation.

Before Taking

As always, your healthcare provider will want to do a thorough medical history and clinical exam before prescribing a biologic therapy. This will help your practitioner make sure that the potential benefits of treatment outweigh potential risks. In some cases, your healthcare provider will need to make sure you don’t have certain risk factors before starting a biologic. People with certain medical conditions might not be able to get biologic treatments. Or you might need to get a screening test for tuberculosis or a screening test for hepatitis. But this won’t be necessary for every type of biologic therapy. Your healthcare provider will let you know what screening tests might make sense for you.

Generally speaking, you shouldn’t be given certain types of vaccines (those which contain any live viral components) while taking biologic drugs that affect your immune system and can make you more likely to get infections. So you may need to get some of these vaccines before starting therapy.

Can Biologics Be Taken With Other Non-Biologic Therapies?

Yes, usually. Biologic treatments are often taken alongside older non-biologic therapies. For example, someone with rheumatoid arthritis might still continue taking methotrexate while adding an additional biologic treatment. In other cases, the biologic treatment will take the place of previous non-biologic therapies. It will depend on your specific situation.

How Are Biologics Administered?

This varies based on the specific biologic product. Currently, most biologics cannot be taken by mouth, though pharmaceutical companies are working to develop oral therapies.

In general, biologics are given as injections or as infusions. You might be able to give yourself an injection under the skin, or you might want the help of a family member.

Biologic therapies are sensitive to heat and light, so carefully follow any preparation instructions given by your clinician.

Intravenous infusions are administered through a vein. These usually take longer, perhaps a couple of hours. These are typically given in a medical office.

In some cases, only a single treatment is needed. In others, the biologic treatment will need to be taken at regular intervals over time.

How Quickly Do Biologics Work?

How quickly a biologic drug works depends on the particular therapy. For example, a shot of insulin begins to work almost immediately. But for something like a biological therapy for rheumatoid arthritis or psoriasis, you might not notice improvements for a couple of weeks or even a month or more. Ask your healthcare provider what you might expect in your particular situation.

What Are Biosimilars?

Because of the way biologic products are manufactured, it is difficult for competing companies to produce products that are exactly equivalent to the biologic therapies first developed. Unlike older chemical compound drugs, most biologics do not have strictly defined generic equivalents. The FDA defines generics as having exactly the same active ingredient as a brand-name drug. Not only that, but they are also bioequivalent, that is, they have the same dosage form, strength, quality, and performance.

Instead, biologics have something called "biosimilars," which were defined by law in 2009. These treatments are approved by the FDA as having no clinically meaningful differences from the original brand name agent. They should work in the same way as the reference product, and they should be just as safe and as effective. Biosimilars are generally less expensive than the original product, but pharmaceutical companies have lobbied against their use, claiming lack of proof of safety and equivalence.

If a biosimilar is available, make sure to talk to your healthcare provider about whether it is the best option for you. It also makes sense to make sure that the FDA has designated the biosimilar as interchangeable with the original product.

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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.
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Additional Reading

By Ruth Jessen Hickman, MD
Ruth Jessen Hickman, MD, is a freelance medical and health writer and published book author.