Scientists think treatment in which children take increasing doses of peanut protein will be approved next year

The first medical treatment for children with peanut allergies is likely to be approved next year but there are concerns about its affordability, even though it consists essentially of peanut flour.

A study in the US and at the UK’s Evelina children’s hospital shows that gradually increasing a tiny initial dose of peanut protein over six months enabled two-thirds of children eventually to eat two peanuts without ill effects. The paper, published in the New England Journal of Medicine, follows a similar, smaller trial in Cambridge, UK, four years ago.

The latest results are from scientists funded by Aimmune Therapeutics, which was launched to investigate this treatment for peanut allergies. They believe they will have approval for their treatment, delivered in a capsule that is broken open and sprinkled over food, in the middle of next year.

The difference between their trial of a treatment they call AR101 in 550 children and those that have gone before “is the rigour with which the whole process was undertaken” said allergist Dr Stephen Tillis, professor at the University of Washington in Seattle and co-author of the study.

“It is a pharmaceutical-grade treatment product. It is not just peanut flour that you can buy somewhere.” It is, he said, “a grade that the FDA [Food and Drug Administration, which licences drugs in the US] here would be satisfied with”.

Children in the trial were given treatment in three phases, beginning with a very low dose, which was increased every two weeks for a minimum of 20 weeks, with daily dosing at home all the way through, up to 12 months.

Most of the children on the trial began with a reaction to anything more than 10mg peanut protein – a US peanut contains about 300mg and a smaller UK peanut about 160mg. By the end of the trial, the median amount tolerated was 1000mg, or about four peanuts. “To me that is astounding,” said Tilles.

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Scientists think children will have to continue to consume peanut protein to remain safe, possibly for life. Peanut allergy is a potential killer. Earlier this month, the owners of a takeaway restaurant in Lancashire were jailed over the death of 15-year-old Megan Lee who suffered an asthma attack after eating food widely contaminated with peanut protein. Two years ago Natasha Ednan-Laperouse died after eating a Pret sandwich containing sesame seeds.

That makes a peanut allergy treatment both much needed and potentially highly lucrative. Tillis says their treatment will not be priced like a biological treatment – which are extremely expensive. “It will not be tens of thousands of dollars, but priced like an innovative new medication,” he said.

Peanut allergy emerged in the 1990s and now affects over 100,000 children in the UK – about one in 50 – and more than 1.5 million in the US. It has been estimated the market for a treatment could be $4.8bn a year.

In Cambridge, Dr Andrew Clark and colleagues, whose Lancet paper in 2014 generated huge excitement, are also working towards a treatment which should come out in a couple of years. “We have commercialised it,” said Clark. He says he hopes theirs will be gentler, pointing out that 20% of children dropped out in the AR101 trial, including 12% because of side effects.

Since their report, they have treated 180 patients privately because the NHS will not fund it. Only four have dropped out, he says. Their treatment, now costing around £17,000 per child, is unlikely to be much cheaper than AR101, but includes the staffing and hospital costs involved in treating children safely.

Dr Michael Perkin, honorary consultant in paediatric allergies at St George’s, University of London, says in an editorial in the NEJM that it is salutary to remember that the treatment used in Cambridge was “a bag of peanut flour costing peanuts”.

“It’s not like this is some sort of fancy wonder drug that’s been created with a monoclonal antibody in some clever laboratory. They’ve got exactly the same peanut flour and shoved it inside a capsule,” he told the Guardian.

But there are dangers in trying to desensitise a child at home. “The ability to flake off the right amount of peanut or buy a bag of peanut flour to do it is going to be fraught with potential hazards. If a parent’s hand wavers they could end up with 10 or 20 or 50 times the dose and trigger a significant reaction,” he said.

It could mean families finding the money to put their child through the first six months with a licensed treatment – and then buying peanuts to keep them protected.

“Certainly that is one scenario,” said Tillis. Small groups in the US were already doing what he called “off-label peanut immunotherapy” – treatment with something that does not have a medical licence. “A lot of those patients end up with some store-bought food.” But, he added: “We don’t know if that is the equivalent of the maintenance dose of AR101.”