Skin patch shows promise for peanut allergy in toddlers

There are no approved treatment options for peanut allergy in Australia, but that may soon change with a new skin patch currently undergoing Phase 3 clinical trials returning encouraging results.
 
Published in the New England Journal of Medicine, outcomes from the EPITOPE trial indicate that the Viaskin Peanut epicutaneous immunotherapy (EPIT) patch has produced ‘statistically superior desensitisation’ compared with placebo when used in children aged 1–3 years.
 
After 12 months of wearing the patch daily – which contained 250 µg peanut protein or 1/1000th of one peanut – children with a diagnosed peanut allergy had treatment responder rates of 67% for the EPIT patch compared to 33.5% among those given a placebo.
 
The authors say this suggests the patch is ‘sufficient to decrease the likelihood of experiencing an allergic reaction following accidental peanut exposure’.
 
From his Hobart practice, GP Dr Nicholas Cooling sees around four to five referred patients with peanut allergy per day.
 
This is a much higher rate than average given his specific interest in allergy, but Dr Cooling nonetheless told newsGP that the ‘average GP’ will still likely see it once a month.
 
‘Food allergy is prevalent – around one in 10 children in Melbourne have a food allergy, and that’s similar to Tasmania. And peanut allergy is on the top four of those,’ he said.
 
‘So around one in 30 or one in 50 kids have a peanut allergy.’
 
The EPIT patch is not the first attempt at tackling peanut allergy, with the US approving a paediatric immunotherapy medicine (Palforzia) in 2020. However, according to Dr Cooling, who is also the Chair of RACGP Specific Interests Allergy, it is unlikely to appear on Australian shores any time soon.
 
‘There are concerns that maybe it’s not effective and also that there are significant rates of anaphylaxis, so we have been hesitant to fund that immunotherapy,’ he said.
 
Given the EPIT patch is still under clinical investigation and not yet approved by the TGA, many hurdles remain before it becomes available domestically. But if approved, the study authors expect it to provide an additional treatment option for patients where the standard of care alone – allergen avoidance and the use of rescue medication – may not be enough.
 
So, what would this mean for GPs?
 
Dr Cooling said although it will be a specialist service for allergists, GPs will still need to know that it is available so they can refer.
 
‘We would have to see what the criteria is, but if the patch does become available, we hope that it would be able to be prescribed by both immunologist allergists but also GPs with a specific interest in allergy,’ he said.
 
‘Hopefully we’ll be able to prescribe it sometime in the next few years … I think it will take a while before it’s available on the PBS.’
 
And despite the promise of a novel therapy on the horizon, he also cautions that all the immunotherapies for peanut currently in clinical trials are not ‘a perfect cure’ for allergies.
 
‘They just desensitise the individual, which means they can have a much higher threshold for having peanuts, or they can often tolerate normal doses of peanut and not have symptoms, but it doesn’t cure them of their allergy, it just helps increase their threshold for tolerance,’ he said.
 
‘What we’re hoping for is therapy down the track that will turn off the peanut allergy and give what we call “permanent tolerance” so they don’t have to have peanuts every day and they can tolerate any amount any time.
 
‘That’s the Holy Grail, and none of these studies have shown that yet.’

The EPIT patch is designed to be worn daily, without restrictions, for a sufficient duration over the course of the treatment period, so children in the EPITOPE study were able to stay active and maintain their regular activities.
 
The study also showed a shift towards ‘less severe’ food challenge reactions seen following 12 months of treatment, with low rates of treatment-related anaphylaxis at 1.6% in the intervention group and none in the placebo group.
 
Dr Cooling notes the proposed patch treatment has advantages compared to other approaches.
 
‘Oral immunotherapy is the [current] way of delivering desensitisation of peanuts to children, and is used a lot around the world in clinical trials and often also by private allergists in their practice because it’s fairly effective and cheap,’ he said.
 
‘But it does also give a lot of gut side effects, whereas the epicutaneous peanut immunotherapy patch … is going to be a stick-on patch on an arm or back, and therefore reduces the risk of gut side effects which is good.’
 
While the EPITOPE study authors state that no approved treatment for peanut allergy exists for children younger than four years of age, and the efficacy and safety of epicutaneous immunotherapy with a peanut patch in toddlers with peanut allergy are ‘unknown’, Dr Cooling said GPs can wait if the patch does become available, and what referral pathways would be.

‘It’s all about knowing they can refer someone on to a therapy that might be effective. They won’t be doing it themselves, but at least they would know that there is now an opportunity to get some treatment for it,’ he said.
 
‘And it’s good GPs can tell patients that option then refer through the pathways to their allergist, immunologist or their GP with a specific interest in allergy.
 
‘It won’t cure the problem, but it just allows them to eat peanuts more safely.’
 
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childhood allergies clinical immunology epicutaneous immunotherapy peanut allergy skin patch