People with inflammatory autoimmune diseases, such as rheumatoid arthritis and ankylosing spondylitis, may be prescribed biologic drugs if traditional NSAIDs (e.g. ibuprofen) or DMARDs (e.g. methotrexate) are ineffective. Biologics can also be used in conjunction with these traditional medications.
How Biologics Work
Before symptoms of inflammation can be seen or felt, a series of biochemical reactions takes place in the body. A biologic drug targets and prevents a specific reaction from happening, stopping the inflammatory process in its tracks.
In contrast to biologics, conventional drugs treat general inflammation (and resulting symptoms like joint pain) after it has begun.
One type of biologic: TNF inhibitors
Protein molecules called tumor necrosis factor (TNF) trigger unnecessary inflammation in people with autoimmune diseases such as rheumatoid arthritis. Biologics called TNF inhibitors contain special protein molecules that, when injected into a patient’s bloodstream, attach to the TNF molecules. When TNF inhibitors attach to TNF, the TNF cannot trigger inflammation.
Biologics Take Time to Work
A patient may notice a decrease in symptoms as soon as 1 week or as long as 12 weeks after starting a biologic, and symptoms may continue to improve for months afterward. For example, many people who take TNF inhibitors feel symptom relief in 2 to 4 weeks, though the full effects of the drugs usually take 3 to 6 months.
It is not unusual for a biologic to become less effective over months or years, as a person’s immune system develops antibodies to the drug. When this happens, a person will notice symptoms gradually coming back. When a biologic loses its efficacy, a doctor may recommend switching to another biologic.
How Biologics Are Given to Patients
Most biologics are liquid medicines administered to a patient by either:
- Injection under the skin. A patient may give him or herself injections at home. In some cases, a family member or other caregiver may give the injections.
- Infusion into the blood stream. This is typically done in a medical office and can take a few hours.
Pharmaceutical companies are working to develop biologics that can be administered with oral pills. The first of these is tofacitinib, sold as Xeljanz, which was approved by the FDA in 2012.
How often a person takes a biologic varies. In general, infusions may be needed once every 4 to 6 weeks. Injections are usually required every week or two.
Storing and Handling Biologics
Every biologic will have storage and handling instructions that must be followed, or the drug will lose some or all of its effectiveness. Most biologics should not be:
- Exposed to rapid temperature changes. For example, do not use a heat source to warm up a drug that has been stored in the refrigerator. Let it gradually warm to room temperature before injection.
- Exposed to multiple temperature changes. For example, people are advised against storing a biologic in a refrigerator, then warming it up to room temperature, and then putting it back into the refrigerator for later.
- Shaken. Rapid shaking is usually not necessary and may be harmful.
Why are guidelines like these necessary? Most medications are made up of small, stable molecules—aspirin molecules have just 21 atoms—but biologics are made up of huge molecules with thousands of atoms. The chemical bonds that hold those atoms together are relatively weak, and they can be broken by rapid temperature changes and other factors. A drug will not work as prescribed if too many if its molecules’ bonds are broken.
Examples of Biologics Available Today
Biologics are categorized by what part of the inflammatory process they target.
TNF blockers are the most common type of modern biologic. TNF blockers include but are not necessarily limited to:
- certolizumab (Cimzia)
- etanercept (Enbrel)
- adalimumab (Humira)
- infliximab (Remicade)
- golimumab (Simponi)
Examples of other biologics (and their mode of action) include:
- tocilizumab (Actemra), targets the interleukin-6 pathway
- anakinra (Kineret), an interleukin-1 receptor antagonist
- rituximab (Rituxan), a CD20-directed cytolytic antibody
- tofacitinib (Xeljanz), first in a class of treatments RA called Janus kinase (JAK) inhibitors
These list change as the FDA approves new drugs and they are introduced to the US market.
Biologics tend to be expensive. For example, a month’s supply of Humira (two doses) can cost around $2,000 without insurance. Some patients may be eligible for coupons and discounts through pharmaceutical companies.