/ Each semi-peanut kernel contains about 150 mg of peanut protein.
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Peanut allergies are food allergies. Accidental exposure to even a small amount of peanut protein is capable of producing severe reactions. For children with these allergies, the killer can also be a cure – as long as it comes in even smaller doses. The results of the clinical trial, published today in the New England Journal of Medicine, show excellent results for a careful desensitization program. Treatment does not cure allergies and comes with significant risks, but it can help children live their lives without fear of activating peanuts in everything they eat.
The principle behind desensitization, or allergenic immunotherapy (AIT), is to give exposure to the body of the allergen in small and gradual increase in dosages, teaching it to react less when recognizing something it sees as an attacker. In 2015, the Journal of Allergy and Clinical Immunology published details of the "international consensus" on the treatment, saying that although the technique is non-controversial for hay, there is insufficient understanding of its use in the treatment of food allergy.
AIT studies of peanut allergies are, but do not provide enough high-quality evidence to become approved treatment. Therefore, the announcement of this phase 3 trial is a great news: it is the final phase that should be carried out through drug testing before the company can apply for the drug to be licensed by regulatory bodies like the FDA. However, this does not mean that the science of this has been done and everyone can go home – there are still many questions to be answered, and often more than one examination before approval is needed.
The peanuts challenge
This study included 66 locations in 10 countries, and they included 551 patients with peanut allergy. Most of these patients – 496 of them – were between 4 and 17 years old, which is part of. All of these participants took part in the challenge of screening foods, where one day they were given either oat protein or masked peanut protein, and then the other food on the second day. The idea behind this was to make sure the participant did not know whether or not they really ate peanuts – and the person giving them food did not know what they ate. The study included only people who reacted to the hidden peanut protein.
Subsequently, the participants were randomized – one-quarter of the placebo group, set to receive identical treatment powder, but without peanut proteins, and three quarters set to receive the treatment. This treatment started as only 0.5 mg peanut protein in the initial dose, and over the course of 24 weeks, it gradually increased to 300 mg – approximately the same as single peanuts. Then came the maintenance phase: 300 mg every day for another 24 weeks.
When the treatment ended, the results were strict. In another food challenge, the researchers tested how high the tolerance of the participants was. This started with low-dose peanut protein and, if the participant was able to take it, increased the dose to the next round. Only eight percent of children in the placebo group did over 300 mg, compared to 77 percent of those in the treatment.
In the next 600 mg round, four percent of children in the placebo group did it, while 67 percent of those in the treatment group. And 2.4 percent in the placebo group can tolerate 1000 mg peanut protein, compared to half of the treatment group. Among the 55 tested adults, differences in food-reaction responses were not statistically significant.
Standing with Epiphen
Exposing a large group of children in food for which they are extremely allergic, is easy to say, not without risks. The trial had a high dropout rate of almost 12 per cent in the active group due to side effects, and almost all participants received treatment responding during treatment, two-thirds of them moderate or severe. This is probably not entirely attributable to the treatment itself, but is higher than the rate in the placebo group, with less than half of them having a moderate or severe event during the trial.
During the final food challenge, five per cent of children in the treatment group had a severe reaction, and 25 per cent had a moderate reaction. This was much lower than the rate in the placebo group – 11 per cent and 59 per cent, respectively – but shows that treatment and testing came with important risks. "This is not something to start at home," writes epidemiologist Michael Perkin in.
A great weakness in the trial is a break in the maintenance period of six months. Investigations on long-term maintenance therapy are ongoing, but at this stage, there is no evidence of how long maintenance of the treatment is likely to be effective and even safe. If long-term maintenance works, it will require constant discipline from patients, probably by the end of their life, writes Perkin: "The main concern about immunotherapy is that the allergenic tolerance induced will be temporary and lost if regular consumption stops."
Despite these warnings, there is no doubt that this is an exciting and welcoming news for kids with peanut allergies. "Most parents will see the regular consumption of a few peanuts by their child as a very small price to pay for retaining the potential threat of systemic anaphylaxis in the bay," says Perkin.
New England Journal of Medicine, 2018. DOI: ().