Peanut allergy desensitization treatment shows success, but for how long?
A new oral desensitization treatment for children with peanut allergies is on the cusp of FDA approval, however questions remain over both the long-term efficacy of the treatment and the ultimate cost for something that is essentially not much different to peanut flour in a capsule.
The newly published article outlines the results from a Phase 3 human trial into an oral immunotherapy treatment for peanut allergies in children. The drug used in the treatment is referred to as AR101, described as "a peanut-derived investigational biologic oral immunotherapy drug". AR101 is essentially not much more than a very controlled dose of peanut protein, with one researcher suggesting it is not much more than just peanut flour, "shoved into a capsule."
This kind of immunotherapy treatment is not new, following much the same process as many allergen desensitization techniques where a tolerance is developed by slowly introducing an allergen in increasing quantities over a period of time. For over a decade this technique has been demonstrated as somewhat effective in moderating peanut allergies, but it is not without significant risks.
The latest Phase 3 trial shows that, despite a very slow dose escalation strategy, a number of subjects reported adverse effects. Over 10 percent of subjects withdrew from the trial due to negative side effects, and 14 percent needed epinephrine at some point to manage negative responses to the allergen.
In an editorial accompanying the published study, Michael Perkin from the University of London notes that the allergen tolerance developed in these kinds of immunotherapy treatments tends to be temporary. Perkin, who did not work on this study, suggests this new treatment may have to be permanent and ongoing for it to remain effective, and the long-term effects of stimulating these kinds of allergen-related antibodies are unknown.
"The longer-term side effects of sustained consumption of an allergen to which the body has produced IgE antibodies remain unknown," writes Perkin. "Current thinking has focused on eosinophilic disease, such as eosinophilic esophagitis, but surveillance and follow-up will be crucial."
The ultimate results of the treatment were mildly positive, with two-thirds of subjects able to successfully tolerate 600 mg of peanut protein at the end of the study. This is generally equivalent to around two peanuts.
"The results of this ground-breaking study are very promising and suggest that we will be able to protect children who are allergic to peanuts from having a severe reaction after accidental exposure," says George du Toit, a King College London researcher working on the project.
The new treatment recalls a similar successful peanut immunotherapy study from 2014. In that study, a team of researchers from Cambridge achieved similar success in slowly desensitizing children to peanut allergy through a controlled dose escalation. However, that earlier Cambridge study used cheap, straightforward peanut flour as its primary allergen.
The new research is funded by a company called Aimmune Therapeutics, which is aiming to commodify AR101, its peanut protein compound. To be fair, AR101 is not just peanut flour, but it is a carefully manufactured peanut protein with specifically controlled dosages. In its lowest dosages, AR101 comes in capsules as small as half a milligram. These are volumes that are not exactly easy to measure for home users trying the same thing with peanut flour. However, Michael Perkin does suggest that the official approval and regulation of AR101 may result in peanut flour being deemed an unlicensed medical product.
"Once a product such as AR101 appears, such regulators will insist that a licensed product be used when it is available, thus preventing the ongoing use of peanut flour itself," writes Perkin.
Due to the potentially billion-dollar market surrounding a prospective peanut allergy treatment, it is no surprise a pharmaceutical company is getting involved, but questions are being asked of the ultimate cost of the treatment. The Guardian notes that a similar peanut allergen immunotherapy treatment currently deployed in the UK costs around £17,000 per child (US$21,700). It's unclear how much the AR101 treatment will cost but it is suspected that it wouldn't be much cheaper, for what is essentially a very measured dose of peanut flour.
In the end, desensitization therapy for peanut allergens is not necessarily the most promising peanut allergy treatment on the horizon, despite the fact that it may be the first to hit the market. Some researchers are looking ways to trick the immune system into switching off its allergic response to peanuts, while one scientist is exploring the use of pulsed ultraviolet light to inactivate the proteins within peanuts that trigger an allergic response.
The new research was published in the New England Journal Of Medicine.
Source: King's College London