Biologics are medications made using living organisms. Biosimilars mimic FDA-approved biologics but may vary in their inactive ingredients.

Biologics and biosimilar medications are a newer form of therapy. Doctors use them to treat, prevent, or cure several conditions, including diabetes, cancer, kidney disease, and various autoimmune diseases.

Creating biologics involves a more complicated process than producing small molecule medications with chemicals.

This article reviews biologics and biosimilar medications and includes information on their use, manufacturing, safety, and effectiveness.

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Biologics are effective and specialized medications made from living cells and organisms. Biosimilars work much like biologics, to the point where doctors can sometimes use them interchangeably.


Biologics can take several forms, including:

  • vaccines
  • cell therapies
  • gene therapies
  • therapeutic proteins
  • monoclonal antibodies

Doctors often use biologics in treating, preventing, or slowing the progress of several conditions or diseases, such as:

The Food and Drug Administration (FDA) regulates the production of biologic drugs just as it does with small molecule medications, such as aspirin or other more traditional medications.

However, biologics are larger and more complex to develop than small molecule medications. Doctors also typically administer them through infusions or injections.


According to the FDA, biosimilars share the same clinical features as biologics and are very similar. Features they share include:

  • how doctors administer them
  • potential side effects
  • dosage and strength

Some biosimilars are interchangeable. With interchangeable biosimilars, a pharmacist can dispense the biosimilar in place of the prescribed biologic.

In short, biosimilars can provide the same treatment effects but are generally easier to develop than the biologics they imitate.

In medication, the term “generic” typically refers to non-branded versions of a given medication.

For example, a person needing a pain reliever can choose between Tylenol and a generic store-brand version of acetaminophen. The two medications are identical on a molecular level.

Biologics are a lot more complex and challenging to produce and reproduce. To complicate things further, biologics can differ in potency and makeup among batches at the same manufacturer.

This means that biosimilars are not generic medications in the traditional sense. Instead, they are a similar alternative to the original biologic.

A doctor needs to prescribe a biosimilar specifically, and a pharmacist cannot substitute most biosimilars for biologics without consent from a doctor as they can with generic medications.

According to researchers from Johns Hopkins, the complexity associated with manufacturing biologics has made many people question whether generic versions would work. However, they noted in 2016 that generic versions of biologics, also known as biosimilars, could provide the same benefits and quality as the original biologic.

Biologics come in several different forms or types. Doctors can use biologics to treat, prevent, or cure a variety of conditions and diseases.

Some common types of biologics include:

  • blood and blood components
  • allergenics
  • recombinant therapeutic proteins
  • somatic cells
  • gene therapy
  • tissues

Some examples include:

Biologics may be made of cells from microorganisms, animals, or humans. They may also be made up of nucleic acids, proteins, sugars, or a combination of these compounds.

Manufacturers create biosimilars to be virtually identical to the referenced biologic. This means they will share qualities such as:

  • doses and strengths
  • potential for side effects
  • administration

As of October 2021, there were 21 biosimilars on the market in the United States competing against eight referenced biologics. Additionally, there are roughly 100 biosimilars in development.

In short, a doctor can prescribe a biosimilar in place of a biologic as long as it can treat the same condition and has FDA approval.

Biologics and biosimilars can treat conditions such as cancer, multiple sclerosis, and other difficult-to-treat conditions.

At the pharmacy

According to the FDA, interchangeable biosimilar medications must go through a lot more testing than other biosimilars. The main difference is that interchangeable biosimilars operate like other generic medications at pharmacies.

This means a pharmacist can substitute the interchangeable biosimilar medication for the referenced biologic without requiring approval from the prescribing doctor, although rules may vary among states. However, the prescribing doctor needs to have specified the drug’s function.

The future: Could biosimilars replace biologics?

The market for biosimilars has grown with the general success of and demand for biologics. Biosimilars open the door for people to get biologic treatment for chronic diseases when traditional medications do not provide enough relief.

According to the Cancer Action Network, biosimilars came onto the market as a more cost effective form of biologics. They are often cheaper because they require less cost to reach the market than the biologics they replicate.

Biosimilars will likely increase in numbers in the coming years, especially as patents expire for existing biologics. This process mimics that of traditional medications. When a brand name drug goes off patent, a less expensive generic usually becomes available.

The FDA puts biologics and biosimilar medications through rigorous testing to ensure quality, effectiveness, and safety.

However, as the American Cancer Society points out, the use of biologics to treat cancer, in particular, is a newer form of therapy. As such, the organization notes that doctors often exercise caution when using them due to unknown, potential long-term side effects.

In addition, biologics and biosimilars can cause some severe side effects. According to an older 2011 research review, the use of biologics and biosimilars might increase a person’s risk of developing certain side effects, including:

  • serious illness
  • lymphoma
  • tuberculosis
  • congestive heart failure

However, the authors of the review also noted that people taking the biologics or biosimilar medications over a short period had no greater risk of serious side effects than people taking placebos.

Many doctors will recommend biologics because of how effective they can be in treating certain conditions.

According to the FDA, biologics are part of the fastest growing sector of medication. This may be due in part to their overall effectiveness in treating conditions that are traditionally difficult to treat, such as cancer and psoriatic arthritis.

Biosimilars have the same effectiveness as the original biologics.

Biologics and biosimilars can offer advanced care for people living with different medical conditions, including cancer, multiple sclerosis, and psoriatic arthritis. However, they may not work for everyone.

The following are some pros and cons a person may wish to discuss with their doctor.


  • Biologics and biosimilars are effective and generally safe to use in several harder-to-treat conditions.
  • It is a fast-growing field of medicine.
  • Biosimilars can be more cost effective than their referenced biologics.


  • The side effects of long-term use are unknown.
  • There is an increased cost compared with some other treatment options.
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Biologics and biosimilars are effective forms of medication that use living cells and organisms to treat, cure, or prevent certain conditions. Doctors can prescribe either a biologic or available biosimilar medication for treatment.

Though biosimilars involve the same effects, doses, and safety as biologics, they are often lower in price.