Peanut Allergy cure? Not quite but there is hope….
This is a super exciting time in the field of food allergies! We are getting closer and closer to treatments and one day, at diagnosis, moms/patients might not have to be told ‘There’s nothing we can do – just avoid the allergens.’
I have been following along the development of two treatments on the horizon that might be available to US patients in 2019, and excited to share these with you here.
Currently there is no FDA approved treatments for food allergy desensitization. Some allergists offer off-label OIT (Oral ImmunoTherapy) in their offices, but the availability vary a lot geographically and there are considerable cost and time commitment (not to mention the possible side effects and the costs/time involved there).
In a nutshell, OIT involves slowly introducing a food allergen into a patient’s diet, which leads to a series of changes to the IgE/IgG antibody levels, some epigenetic changes which then lead to a shift from Th2 (the ‘allergic’) immune response to Th1 (the not-allergic) immune response. The end result is that the person starts to be able to tolerate the food and not develop anaphylaxis when ingesting it in small quantities. It can be very effective and many allergists have had great results.
The main downside to OIT currently is that a maintenance dose is necessary even after you complete the program (in most cases), and if this is missed, there is a chance that the allergy will come back. There can also be side effects and symptoms during the up-dosing process (i.e. building up the amount of peanut protein), the commonest is abdominal pains, as well as vomiting, hives and the other usual allergy symptoms.
The big upside is of course safety!
The two treatments currently on the horizon are:
a) Viaskin – this is a skin patch developed by a company called DBVT:
- The peanut patch is currently in Phase III trial (almost ready for FDA filing)
- Phase III trial now on children between ages 4-11 years (because the phase II study showed the efficacy was much lower in those 12 years or above)
- The company is also developing patches for egg and milk allergy too which may be available later (in a few years). If you want to read the efficacy study it is here
- The way it works is this: we have immune cells in our skin called Langerhan cells. These have ‘tentacles’ which reach out and sense out ‘enemies’ to protect us. The patches deliver peanut proteins to these immune cells in the skin and therefore cause the similar changes to the immune system as OIT.
- The phase II trial showed that 46% of those using the 100mcg patch, 48% using the 250mcg patch met the criteria they set for ‘peanut desensitization’, vs just 12% in the placebo group. This was after 1 year of using the patches, but the follow up study showed that response rate was 80% if treatment was extended to 24 months.
- The major advantage over OIT is the side effect profile – some patients reported low grade local reactions of the patch, but the patches were not associated with EoE (see above) in mouse models.
b) ARA101 – developed by a company called AIMMUNE, a product that is:
- capsules comprising of highly characterized, pharmaceutical grade peanut OIT formulation. The protein is standardized and tested for Ara h1, h2 and h6 (3 of the individual peanut components) to provide consistent dosing.
- it probably carries the same side effect profile as OIT (i.e. possible EoE, abdominal pains, and other symptoms of allergic reactions like hives)
- has a wider age range in the Phase III trial (4-17 years of age) so may be available to a wide age range if FDA approved.
- The company also developing a similar product for eggs.
Now, as you can see – it appears that the patches MAY be a little less effective at the one year mark (48% vs 79%) but the end points used are slightly different so it’s difficult to compare side by side – to be fair, perhaps it just takes longer to reach desensitization with patches (as shown by the follow up study). The fact that it did not cause EoE in mouse models is a big plus for me, although whether that data can be extrapolated to humans remains to be seen in the latest trial results.
Perhaps more exciting than the two products above is the PPOIT (Probiotic Peanut OIT) study by Professor Teng in Australia, published in the Lancet just in August (2017). You may have heard this already, or seen it on my FB page – in this study, they combined Lactobacillus Rhamnossus (LGG – a strain of probiotic that I have been giving my kids for years now and wrote about in my other blog posts), with an OIT program. I don’t know the dose of LGG they used but apparently it is equivalent to 20 tubs of yoghurt a day (!) … huge quantities and I wouldn’t recommend for you to try this dose at home without a doctor’s guidance.
However, what they found was that those who received probiotics along with OIT were more likely to demonstrate sustained tolerance to peanuts. Sustained tolerance is where you continue to be able to eat peanuts without a maintenance dose (and if you remember from above, most OIT graduates are required to stay on a maintenance dose or risk the allergy coming back). So this is kind of like the holy grail of allergy treatment, where we would want our allergic children to reach – able to tolerate peanuts without having to remember to take the maintenance dose.
However, the study was small (48 patients) and one issue is that they did not challenge the patients at the beginning of the study i.e. we don’t know whether and how much peanut protein they tolerated at baseline, before they started treatment.
They are now undertaking a larger study to look into it more, and the hope is that if the results are replicable then it could be extrapolated to treatment modalities.
So, our best hope is for a product that can desensitize our kids PLUS induce long term tolerance. Easier said than done but watch this space! Lots of exciting developments!
Disclaimer: I do not work for these companies and have not been involved in their research trials. The blog post is based on their research trial results published online and news announcements made. Conclusions and opinions are my own and not that of the companies.