What Are Biologic Drugs for Asthma—and Do You Need One?

For people living with severe asthma whose symptoms persist despite standard treatment, biologic medications offer an important step forward—fewer flare-ups, less reliance on steroids, and in some cases, significantly reduced need for daily inhalers.

Biologics, a newer class of therapies, are not a cure, but experts say these targeted drugs can dramatically improve quality of life. They work by blocking specific immune system molecules that drive airway inflammation. For the right patient, Yale Medicine specialists say the impact can be substantial.

“You can start someone on a biologic and greatly improve their asthma control. It can change their life,” says Sandra Zaeh, MD, MS, a Yale Medicine pulmonologist who specializes in asthma.

Most people with asthma manage their symptoms with inhalers, which reduce inflammation and open the airways. But for some people, even high-dose inhaled medications don’t prevent ongoing symptoms or flare-ups. That’s typically when biologics enter the picture.

“If you’re using your inhaler as prescribed at a high dose and you’re still having symptoms—or even one flare requiring prednisone a year—that’s not where we want patients to be anymore,” says Lauren Cohn, MD, a Yale Medicine pulmonologist and asthma specialist. “In the past, we might have monitored symptoms for longer. Now we’re moving to biologics earlier.”

That, Dr. Zaeh adds, is especially meaningful for people who have needed repeated courses of prednisone, an oral steroid often used for severe asthma flare-ups that is associated with long-term risks, including osteoporosis, high blood sugar, and cardiovascular complications.

“There’s strong evidence that repeated use of prednisone increases the likelihood of complications such as osteoporosis and diabetes,” Dr. Cohn says. “Even a few short courses of prednisone over time carries risks.”

Biologic medications are drugs made from living organisms, such as cells derived from animals, plants, or bacteria. Many work like antibodies, the proteins your immune system naturally produces to recognize and neutralize specific molecules in the body. In asthma, biologics are designed to block specific molecules that trigger airway inflammation that leads to coughing and wheezing.

Unlike inhalers, which act broadly in the lungs, biologics focus on the underlying pathways driving the disease.

Biologics for asthma have been in use for more than a decade. Several are now available, including dupilumab (Dupixent) and mepolizumab (Nucala), each targeting a different inflammatory pathway. Some are also used to treat related conditions such as eczema and chronic sinusitis with nasal polyps.

Most are given by self-injection, typically every two to eight weeks depending on the medication. A newer option can be administered as infrequently as every six months.

“We usually teach patients how to do the self-injections in clinic,” Dr. Zaeh says. "After that, most people are comfortable managing it on their own.”

Biologics are not one-size-fits-all. Deciding whether to use one—and which one to try—depends on how well your asthma is currently controlled and what type of asthma you have.

The first consideration is whether standard treatment is working. If you’re still having symptoms or needing corticosteroid treatments for flare-ups, that’s a signal that a different approach may be warranted.

From there, doctors use testing to pinpoint the type of asthma and which inflammatory pathways are involved. Relevant factors include:

• Blood eosinophil levels—eosinophils are a type of white blood cell associated with allergic and airway inflammation
• Markers of airway inflammation, measured through breathing tests or blood work
• Coexisting conditions, such as nasal polyps or chronic sinus disease

Most available biologics are particularly effective for patients with what's called "type 2" asthma—a form driven by allergic or eosinophilic (inflammation related to eosinophils) inflammation, which is also the most common type in adults with severe disease.

“If someone’s asthma is not controlled, we can usually get them under control,” Dr. Cohn says. “And once they are, they can often taper down—and sometimes even come off—their inhalers.”

One of the most striking effects of biologics is how much they can reduce the need for other treatments, including inhalers that many people assumed they would need indefinitely.

“We used to tell people you don’t go on a biologic to stop your inhalers,” Dr. Cohn says. “But in reality, that’s often what happens.”

Once asthma is well-controlled on a biologic, some patients—under their physician's guidance—are able to taper down and sometimes discontinue their inhalers.

Biologics are generally considered safe, with relatively mild side effects compared to long-term oral steroid use.

“The most common issue is a local injection-site reaction,” Dr. Zaeh says. But this redness, mild swelling, or tenderness typically resolves quickly.

Serious allergic reactions, including anaphylaxis, are possible with any medication. With biologics for asthma, the risk is very low—less than 1%, Dr. Zaeh adds.

If one biologic doesn't work well or causes problems, switching to another is often an option.

Despite their benefits, biologics can be expensive, and whether they're accessible depends largely on insurance coverage.

“These medications are very costly,” Dr. Cohn says. “If you’re uninsured, they can be difficult to obtain.”

That said, many patients access treatment through insurance plans, specialty pharmacies, and manufacturer patient-assistance programs.

“At Yale Medicine, we have pharmacists who help navigate coverage, copays, and financial assistance,” Dr. Cohn says. “There are often ways to make these therapies accessible.”

Patients who are interested should ask their care team or their insurer about coverage criteria and assistance options before assuming a biologic is out of reach.

While biologics can substantially improve asthma control—sometimes dramatically—they do not cure the underlying condition.

“If you stop these medications, asthma typically comes back,” Dr. Cohn says.

Research is ongoing into how long patients need to stay on biologics and whether tapering is possible for some over time. For now, most patients who benefit from these medications continue them long-term. “There’s a lot we’re continuing to learn,” Dr. Zaeh says. “But for the right patient, biologics can make an enormous difference.”

If you have severe asthma that isn't well-controlled—meaning you're still having symptoms, using oral steroids for flare-ups, or experiencing significant limitations on daily life despite standard treatment—it's reasonable to raise the question with your doctor or ask for a referral to a pulmonologist or asthma specialist.

“If you’re still having symptoms or needing steroids, you should ask your doctor about newer treatment options,” Dr. Zaeh says.