Ask the Allergist: How Do Biologics Work?

My asthma is worsening. I recently read about new biologic medications. How do they work? And how will my doctor determine if biologics are right for me?

Rohit Katial, MD: First let’s step back for a moment: Asthma is a disease of inflammation of the breathing tubes. The inflammation is immune cells coming into the airways, causing them to get inflamed, and then to get twitchy and narrow. You cough and wheeze, and there’s mucus.

Inhaled corticosteroids continue to be one of the primary treatments for asthma. They are an effective daily medication to help keep asthma symptoms under control. If you’re still experiencing symptoms even with medication, then biologics are the next step.

The biologics that have come to market in recent years are for severe asthma. They target chemicals that knock out the fuel for immune cells, with the idea being that if we knock out the fuel, then those cells no longer exist and the airways don’t get inflamed.

I recommend severe asthma patients go see a board-certified allergist to review their Asthma Action Plan, the medications they take, and how they take them. Sometimes incorrect inhaler technique is the reason why medications are not effective. An allergist evaluation should be comprehensive, including what your asthma triggers are, whether you’re allergic, and what asthma medications you take daily.

When all that is done, biologics are an exciting option. One biologic, available since 2003, is omalizumab. It’s an injectable biologic that blocks IgE, the antibody that causes allergies.

In the last couple years, two new biologics – mepolizumab and reslizumab – arrived on the market. They both block the same chemical, interleukin-5 – this is the fuel for cells called eosinophils that drive the airways and breathing tubes to get inflamed.

Mepolizumab is an injection in the arm, the same as omalizumab. Reslizumab is an intravenous infusion, in which the medication is delivered through an IV.

Biologics are very specific medications – they’re not for everyone. That’s where the allergist can play a role in determining the right medication for you. With biologics, you have to take into account that you must go to a doctor’s office every month to receive the injection or infusion. So it’s important to discuss potential risks and benefits, the pros and cons, of taking these medications.

Rohit Katial, MD, FACAAI, is a board-certified allergist and immunologist and co-director of the Asthma Institute at National Jewish Health in Denver. He is also a member of the Board of Regents for the American College of Allergy, Asthma and Immunology (ACAAI).

Have a medical question? Email or write to Ask the Allergist, Allergy & Asthma Network, 8229 Boone Blvd., Suite 260, Vienna, VA 22182.


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