A systematic meta-analysis of a dozen trials into the efficacy of an oral immunotherapy treatment designed to reduce allergic reactions to peanuts has concluded the treatment may work in clinical environments, however, it paradoxically results in patients suffering from more real-world adverse allergic events than people who simply avoided peanuts altogether.
Over the last decade peanut desensitization therapy has been slowly progressing through research trials as a potential treatment for children with severe allergic reactions. The idea is that a tolerance can be established by very slowly administering small quantities of the allergen in increasing quantities over a period of time. One specific treatment using "a peanut-derived investigational biologic oral immunotherapy drug" is on the cusp of FDA approval in the United States.
However, there are serious questions hovering over the efficacy of these kinds of peanut desensitization treatments. While many trials demonstrate some subjects being able to safely ingest small amounts of peanuts following long-term treatment, it is unclear how long these effects last, and whether they are effective in real-world eating environments.
This new meta-study collected data from 12 randomized controlled trials, totaling over 1,000 patients. The goal was to examine the disconnect between endpoint goals in specific trials that demonstrate successful peanut tolerance, and the volume of subsequent allergic reactions in the years following treatment. The study concluded that those subjects who initially successfully completed an oral immunotherapy course ultimately reported more real-world allergic responses.
"When you look at the data, it is clear that people who were on peanut oral immunotherapy, known as OIT, had many more allergic reactions compared to those that only avoided peanut, both mild ones such as vomiting all the way to severe reactions like anaphylaxis," explains Derek Chu, lead author on the new study from McMaster University. "This was despite oral immunotherapy being able to cause desensitization."
Chu does note that the goal of this study is not to, "denounce current research in oral immunotherapy", but instead better understand how to measure the treatment's success. The researchers do not hypothesize why successful oral immunotherapy could paradoxically cause a person to suffer more real-world adverse reactions, but Chu does suggest these results illustrate the major differences between administering peanuts in controlled clinical settings, and real-world accidental dietary exposures.
"Looking at all the studies, we consistently found that the protection from oral immunotherapy was incomplete and variable, with people being able to eat peanut in the clinic, but, in the real-world they ended up having reactions," says Chu. "This was probably because the way people eat in the real world is different than how they eat in a clinic setting. In many instances there was no known reason for a loss of protection and patients had unpredictable reactions."
This new meta-study is not without its own limitations. Alongside an admittedly small sample size is the problem of many assorted trials with different study designs being grouped together. In an accompanying editorial, Graham Roberts and Elizabeth Angier from the University of Southampton point out that the large differences in the studies assessed make it difficult to confidently generate a clear conclusion from the data.
Roberts and Angier, who did not work on this new trial, ultimately suggest early introduction of allergens into an infant's diet could be the better long-term solution in battling the dangers of peanut allergies.
"… we should not forget that we now know that the early introduction of peanut products into the infant diet can prevent most cases of peanut allergy," Roberts and Angier write. "Moving forward we need to develop implementation strategies to reduce the number of patients with peanut allergy."
The new study was published in the journal The Lancet.
Source: McMaster University