A small daily dose of peanut can help adults to overcome life-threatening allergies, a trial has shown.
The oral immunotherapy given under strict supervision of allergy specialist teams found two thirds of patients were subsequently able to tolerate eating up to five peanuts.
Already shown to be successful in children, this is the first preliminary evidence that the approach might also be used to desensitise adults with peanut allergy, the UK researchers said.
The Phase II trial included 21 adults aged between 18 and 40 with a clinical diagnosis of peanut allergy at Guy’s and St Thomas’ NHS Foundation Trust.
In the clinic, participants received the first dose of 0.8mg peanut flour mixed in with food, then 1.5 mg 30 minutes later followed by 3mg a further 30 minutes later.
Those who were able to tolerate 1.5mg or 3mg of peanut flour continued on a daily dose at home for a fortnight.
Every two weeks those taking part in the study returned for supervised doses of more peanut protein, increasing from 6mg to 1g which equals four whole peanuts.
Where participants could tolerate 50-100mg of peanut protein, they were switched to eating whole peanuts, peanut butter or peanut products – the first dose of which was under supervision of the clinical team who were funded by the National Institute for Health Research.
After reaching a dose of 1g they remained on this for at least four weeks before having a a double‐blind placebo‐controlled food challenge under close supervision to test their tolerance.
They daily dosing for at least three months before exiting the trial or taking up the option of continuing with post-study research, the team reported in Allergy.
Overall 67% of participants were able to consume at least 1.4g peanut protein without reacting after which they could consume peanuts every day at home to remain desensitised.
Last year a detailed study from the Food Standards Agency found one in 20 adults in the UK has a clinically confirmed food allergy.
Chief investigator Professor Stephen Till, professor of allergy at King’s College London, said: ‘Constant fear of life-threatening reactions place a huge burden on people with peanut allergy.
‘Although peanut immunotherapy is known to be effective in children, this trial provides preliminary evidence that adults can also be desensitised and that this improves quality of life.
‘The average tolerated dose of peanuts increased 100-fold over the course of the trial.’
He explained that the efficacy rate was broadly in line with peanut oral immunotherapy trials in children.
‘The next stage of the research will be confirming this in larger trials, and also identifying the group of adult patients who would most likely benefit from oral immunotherapy, and see whether it can lead to long-term tolerance in this age group.’
Lead author Hannah Hunter, a specialist allergy dietitian from Guy’s and St Thomas’ NHS Foundation Trust, said: ‘Living with peanut allergy is a huge burden due to the need for constant vigilance and the risk of accidental exposures.
‘We found that quality of life significantly improved after oral immunotherapy and fear of food also decreased. Many participants who completed the trial told us that the treatment had been life-changing and they were no longer living in fear.’
