For people with drug or food allergies, anaphylaxis is a danger that’s always lying in wait. This sudden and severe reaction can occur within seconds or minutes of exposure to an allergen, leading to life-threatening anaphylactic shock that causes blood pressure to drop severely and/or the airway to close up. These severe reactions affect one in 50 Americans, according to research, though many experts believe that number is actually closer to one in 20.
Until recently, an injection of epinephrine, using an EpiPen, has been the only treatment for anaphylaxis. Earlier this year, the FDA approved a drug called Palforzia to help reduce the risk of allergic reactions in children with peanut allergies.
Now: A new study suggests that an oral medication being used to treat some cancer patients may become the first pill to prevent anaphylactic reactions that result from any drug or food allergy.
Study details: In the new research, published in The Journal of Clinical Investigation, researchers from Northwestern University found that medications known as Bruton’s tyrosine kinase (BTK) inhibitors successfully blocked anaphylaxis in human test-tube mast cells, which release allergy-causing substances in response to an allergen.
When an allergy exposure occurs, BTK (an enzyme) activates the release of histamine and additional substances in mast cells and other cells. BTK inhibitor drugs block this trigger. A BTK inhibitor was also shown in the study to block anaphylaxis in mice that had transplanted human mast cells in a so-called “humanized” mouse model.
“This pill could quite literally be life-changing and life-saving,” explained Bruce Bochner, MD, the study’s senior author and Samuel M. Feinberg Professor of Medicine at Northwestern University Feinberg School of Medicine in Chicago. “Imagine being able to take medication proactively to prevent a serious allergic reaction.”
Previous research involving humans uncovered similar responses. For example, cancer patients who were allergic to airborne allergens, such as cat dander or ragweed pollen, and took the BTK inhibitor ibrutinib (Imbruvica) had allergy skin test reactions that were reduced by 80% to 90% within one week. Adults without cancer who took the drug for a few days also had reduced food allergy skin test reactions.
What’s ahead: Human clinical trials will be needed to confirm that BTK inhibitors can be used to prevent allergic reactions. To do this, the researchers plan to give study participants who are allergic to a medication or food a BTK inhibitor then do skin testing to see if allergic reactions are reduced or eliminated.
Caveats: BTK inhibitors, which are FDA-approved to treat blood cancer, are not currently approved for use in children, who are often affected by food allergies (including milk, eggs and tree nuts) and drug allergies (such as antibiotics and antiseizure medication). Cost is also an issue. At $500 a day, using the drug preventively on an ongoing basis would be prohibitively expensive at its current cost.
Still, if these issues can be resolved and the drug proves effective in further research, people who have lived in fear of having a serious allergic reaction may have their worries removed by simply taking a daily pill.
Source: Study titled “Bruton’s Tyrosine Kinase Inhibition Effectively Protects Against Human IgE-Mediated Anaphylaxis,” by researchers at Northwestern University Feinberg School of Medicine in Chicago, published in The Journal of Clinical Investigation.