How Are Biologic and Small Molecule Drugs Different?
Key takeaways:
Biologics are medications that come from living sources, like plant or animal cells. They’re given as injections or infusions, and they tend to be expensive.
Most available medications are small molecule drugs. They’re made from chemicals, so they’re easier to make than biologics. Many are available as lower-cost generics.
Both biologics and small molecule drugs have their place in medicine. But they’re handled differently by the FDA.
Most medications on pharmacy shelves are considered small molecule drugs. They’re made from chemicals and have simple structures. But you may be surprised to learn that not all medications are like this.
Biologics are medications that come from natural sources instead of chemicals. Vaccines, certain injectable medications, and even insulin are considered biologics. They’re more complex and can be used to prevent and/or treat a number of conditions.
But what are the key differences between biologics and small molecule drugs? Keep reading to learn more.
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What are biologic drugs?
Biologics are medications derived from living sources. This includes animals, humans, and other living organisms. They can be made of proteins, sugars, and other substances. Biologics are commonly used to treat autoimmune disorders and cancer. But they’re also used to treat and/or prevent conditions like migraine headaches, COVID-19, and transplant rejection.
Vaccines are also biologics. And after the definition was officially changed in March 2020, medications like insulin are considered biologics, too.
Biologics are typically given as an injection under the skin or into a muscle. Some are given as an intravenous (IV) infusion into the vein. In some cases, you may be able to give yourself a biologic injection. Otherwise, you’ll need to have it administered by a healthcare provider.
For now, biologics are currently limited to injections and infusions. Oral biologics have been researched for decades. But they aren’t available quite yet due to their complex nature.
What are the pros and cons of biologics?
Before getting started on a biologic, your healthcare provider will make sure it’s the best choice for you. That’s because biologics aren’t for everyone. Each biologic has its own benefits and risks that should be discussed with your healthcare provider. Below are a few things to know.
Pros
Biologics have made a significant impact on the treatment of complex conditions. In some cases, they’re first-choice treatments to slow conditions from getting worse. And recently, they’ve been important in the fight against COVID-19.
Biologics can be made to have specific targets. These targets can include proteins on cancer cells, substances that worsen your condition, and more. Because of this, they’re versatile in how they can be designed and used. They also provide more treatment options beyond symptom management. For example, biologics are being explored to slow the progression of Alzheimer’s disease.
Some biologics leverage your own immune system to better find and destroy these targets. This is called immunotherapy. Immunotherapy has led to new innovations in cancer treatment.
This also includes the development of personalized cancer vaccines. These are vaccines that are made specifically for you. They are a type of immunotherapy that can help treat (not prevent) certain types of cancer.
Cons
As with most medications, biologics also carry some risks. For example, biologics used to treat autoimmune disorders work by suppressing your immune system. This can put you at higher risk for infections, including serious ones. You’ll typically be screened for certain infections before and during treatment.
There’s also a risk of your body making antibodies against certain biologics over time. These are called anti-drug antibodies. This means that these antibodies bind to the biologic and prevent it from working. You may need to change to a different medication if this happens.
Biologics also tend to be expensive due to their complexity. And you may need to use a specific type of pharmacy to fill your prescription, too.
What are some examples of biologic drugs?
Biologics span many different medical conditions. And the list continues to grow as more are brought to market. Below are a few examples:
Autoimmune disorders: Humira (adalimumab), Enbrel (etanercept), and Remicade (infliximab)
Cancer: Keytruda (pembrolizumab), Tecentriq (atezolizumab), and Herceptin (trastuzumab)
Diabetes: Lantus (insulin glargine), Humalog (insulin lispro), and Novolog (insulin aspart)
What are small molecule drugs?
Most available medications are considered small molecule drugs. They’re made from chemicals and have low molecular weight. This helps them easily enter your cells so they can start working. You can find them as tablets, creams, liquids, and more.
What are the pros and cons of small molecule drugs?
As with biologics, there are a few things to know about small molecule drugs.
Pros
Small molecule drugs are typically easier to make — and copy. Copied versions of small molecule drugs are called generics. Generics provide lower-cost options with similar clinical benefits. In fact, 90% of prescriptions filled in the U.S. are for generic medications.
By comparison, manufacturers can’t make exact copies of biologics. They can make medications that are very similar to biologics, called biosimilars. More on this later.
Small molecule drugs are also first-choice treatments for many different medical conditions. That’s because many of them have been used for years and studied extensively. They’re often a more cost-effective option compared to biologics.
Cons
Small molecule drugs can also have targeted effects, but not quite as targeted as biologics. Because of this, they can have unintended off-target effects. This can result in side effects and toxicities.
For example, beta blockers can target parts of your heart to help lower heart rate and blood pressure. But there are similar targets throughout your body that can also interact with them. This can cause side effects like nausea and constipation.
What are some examples of small molecule drugs?
Small molecule drugs have been around for a long time. They’re used to treat many conditions, from high cholesterol to allergies. Examples of small molecule drugs include:
High cholesterol: Lipitor (atorvastatin), Crestor (rosuvastatin), Zetia (ezetimibe)
Allergies: Benadryl (diphenhydramine), Allegra (fexofenadine), and Zyrtec (cetirizine)
Erectile dysfunction: Viagra (sildenafil), Cialis (tadalafil), and Levitra (vardenafil)
It can be easy to confuse biologics and small molecule drugs, especially when both are used to treat a condition. For example, Xeljanz (tofacitinib) is a small molecule drug used to treat autoimmune conditions. But it’s sometimes incorrectly categorized as a biologic.
What are the differences between biologic and small molecule drugs?
Both biologics and small molecule drugs play important roles in medicine. In addition to what we’ve covered above, there are several notable differences between them.
Approval pathways and exclusivity
Biologics and small molecule drugs are both used to prevent and treat certain medical conditions. And they both go through clinical trials to show safety and effectiveness. But their FDA-approval pathways are different. They’re also regulated by different centers within the FDA.
Small molecule drugs are regulated by the Center for Drug Evaluation and Research (CDER). New drugs go through a New Drug Application (NDA) for approval. Through this process, the FDA determines if the medication’s benefits outweigh its risks. They also ensure the manufacturer has proper controls in place to make the medication.
After NDA approval, the FDA grants a period of exclusivity. This means other manufacturers can’t make generic versions of the medication. While some exclusivity can be longer, the typical period is 3 to 5 years.
Biologics are regulated by the Center for Biologics Evaluation and Research (CBER). They go through a Biologics Licensing Application (BLA) before being approved for marketing. There are many similarities with the NDA process. But the BLA process has more requirements around manufacturing. That’s because biologics are more complex and harder to make.
After BLA approval, the FDA grants a longer period of exclusivity. For new biologics, it’s at least 12 years before a manufacturer can make a similar product.
Generics vs. biosimilars
Biologics and small molecule drugs are also handled differently when they’re “copied” by another manufacturer. Generic small molecule drugs are approved through an Abbreviated New Drug Application (ANDA). But there’s a different pathway for biologics.
Instead of generic versions, biologics have biosimilars. Biosimilars are highly similar to another FDA-approved biologic. You should expect the same clinical benefit from a biosimilar. They also tend to be less expensive. But, not all biosimilars are available right now.
In addition to exclusivity, new medications can have patent protection for 20 years. For biologics, this means that exclusivity might end, but manufacturers still can’t market a biosimilar. For example, Humira has seven biosimilars that won’t be available in the U.S. until 2023.
Cost
As mentioned earlier, biologics can be expensive. And while small molecule drugs can also be expensive, lower-cost generic options may be available. GoodRx offers many ways to save on both brand-name and generic medications.
As mentioned above, biologics can have biosimilars. On average, biosimilars tend to be 27% less expensive than their reference biologic. But this doesn’t mean they’re cheap. And a biosimilar version of your biologic may not be available yet. Yet, a biologic may be the most cost-effective treatment option for your condition.
The bottom line
Small molecule drugs are made from simple chemicals. And biologics are made from natural sources. They’re both regulated by the FDA, but they go through different approval pathways.
Most medications available today are small molecule drugs. But more biologics have been hitting the market as of late, changing how we treat complex conditions. You may be taking a biologic, small molecule drug, or both as treatment.
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