Kate Johnson

February 27, 2015

HOUSTON — The risk for adverse events during peanut oral immunotherapy is high in people with allergic rhinitis and those who react strongly to a peanut skin-prick test, new research shows.

This limitation "needs to be properly addressed before the clinical community begins using it for food allergy," said lead investigator Yamini Virkud, MD, from Massachusetts General Hospital in Boston.

"We hoped to find clinical features that would predict who would be at greater risk for more problems," she told Medscape Medical News.

The study results were presented here at the American Academy of Allergy, Asthma & Immunology 2015.

"These findings may influence how we counsel patients on the front end" of immunotherapy trials, session moderator Amy Scurlock, MD, from Arkansas Children's Hospital in Little Rock, told Medscape Medical News.

Dr Virkud and her colleagues conducted a pooled analysis of three peanut oral immunotherapy trials that had similar protocols, all involving 1 year of build-up dosing followed by 3 to 4 years of maintenance dosing.

Overall, the adverse event rate was 80%. Specifically, 49% of the 104 subjects experienced gastrointestinal symptoms, 42% experienced systemic symptoms, and 20% withdrew from their trial because of adverse events.

High Risk

The risk for adverse events was almost 3 times higher in patients with pre-existing allergic rhinitis than in those without (relative risk [RR], 2.7; P < .001). In addition, there was a 1.4-fold increase in the risk for adverse events with every 5 mm increase in wheal size on a peanut skin-prick test (P = .01).

In other words, "if a person with no allergic rhinitis receiving oral immunotherapy has 10 adverse events, then a person with allergic rhinitis will have 27. And if a person with a 5 mm wheal has 10 events, then a person with a 10 mm wheal will have 14," Dr Virkud explained.

During the build-up phase of oral immunotherapy, allergic rhinitis was a risk factor for adverse events (RR, 2.0; P = .03), as was larger wheal size (RR, 1.4; P = .01).

 
We all have known intuitively that people who have other allergic disorders may have increased symptoms with oral immunotherapy, but it's nice to see it modeled and proven like this.
 

During the maintenance phase, wheal size was no longer a significant risk factor. However, asthma more than doubled the risk for an adverse event (RR, 2.2; P =0.04), and the association between allergic rhinitis and adverse events became stronger (RR, 6.5; P < .001).

Interestingly, there was a significant difference in the seasonal distribution of adverse events; patients with allergic rhinitis experienced most events in January and September, and those without allergic rhinitis experienced most events in April and October (P < .001).

For patients with allergic rhinitis, the risk for an adverse event was higher in a peak month than in a nonpeak month (RR, 1.4; P < .001), Dr Virkud reported.

"One thing we were surprised to note was that peanut-specific IgE is not related to the rate of adverse events," she explained.

"We need to validate the findings before we consider not recruiting patients with allergic rhinitis for oral immunotherapy," said Dr Scurlock. However, "I think this may be helpful in counseling patients when we put them in a study."

"We all have known intuitively that people who have other allergic disorders, like allergic rhinitis, may have increased symptoms with oral immunotherapy, but it's nice to see it modeled and proven like this," she said. "We do need to be very aware of the higher potential for adverse reactions in these people."

Dr Virkud and Dr Scurlock have disclosed no relevant financial relationships.

American Academy of Allergy, Asthma & Immunology (AAAAI) 2015: Abstract 510. February 22, 2015.

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