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Saturday, January 13, 2007

Current Peanut Allergy Research

This week on NoPeanuts we have had discussion on whether the food allergy focus should be on peanuts. There was debate about whether I should focus on peanuts so much or instead balance my comments and articles across all forms of food allergy. Though I am certainly empathetic to all food allergies, especially when we think of stories such as that of Sabrina Shannon, the NoPeanuts family is primarily concerned with peanut allergy right now as that is what triggered the events of Boxing Day.

As part of our journey I have been extensively reading, pondering and discussing the ongoing research into the causes and possible treatments of peanut allergy anaphylaxis. As I get deeper in to the research I will certainly pass along what I learn on other food allergies - remember, we are also challenged with anaphylaxis to uncooked egg-white.

Though somewhat dated, I think it is worth highlighting a great article in the Wall Street Journal in October 2006 titled "Researchers Uncertain How To Tame Peanut Allergy" by Jame Zhang. The article covers many possible solutions but three jumped out as being of particular interest:

- Drug Development
- Immunotherapy
- Genetically Modified Peanuts

In the quoted, highlighted text below I have taken excerpts the WSJ article:

Drug development:
"An approved asthma drug, Xolair, may be useful in treating peanut and other food allergies; injected into patients, it would reduce certain antibodies that are thought to cause anaphylactic food allergy. Last year, though, clinical trials came to a halt after two children, who had been given peanut protein in a screening to gauge the severity of their allergy, experienced anaphylactic reactions. The drug's makers — Genentech, Novartis and Tanox — are working with the Food and Drug Administration to design a new trial, Genentech says."

This drug has actually had a controversial history. It 'took over' from TNX-901 after a legal battle between multiple drug development partners - as documented by Time in 2003. Given that it is one of the only drugs I am aware of geared toward peanut allergy it will be interesting to see if anything actually transpires. Based on the halting of the clinical trial (see above) and the fact that Xolair did not begin life as a peanut allergy drug in the first place, I would not hold out on waiting for this drug to hit a pharmacy near you. It is also worth noting that, per the Time article, the annual cost of treatment would be a whopping $10,000!

So if there is not a drug treatment available (not that I would necessarily take that option for our daughter anyway), what about the possibility of a vaccination or immunotherapy? The research actually seems quite promising in this area:

Immunotheraphy / Vaccination:
Two researchers — Wesley Burks, chief of pediatric allergy and immunology at Duke University Medical Center, and Hugh Sampson, his counterpart at New York's Mount Sinai School of Medicine — are trying to create a vaccine. They have slightly modified the three peanut proteins responsible for most reactions so they don't trigger such strong reactions from human mast cells. By administering the modified proteins to subjects in slowly increasing doses, they hope to condition their immune systems to tolerate more. They have tested the therapy on mice and plan to start on humans in a year or so.

Another experimental therapy aims to reduce the severity of reactions. Burks's team administers powdered or liquid peanut proteins to patients in incrementally increasing doses, starting with 0.001 peanut the first day, to one whole peanut six months later. They hope one day to develop a drug or a physician-administered therapy. In a trial completed on eight patients, Burks says the subjects tolerated 13 peanuts before experiencing a reaction — enough, in theory, to save an allergic child's life in case of accidental ingestion."

I actually have communication into Dr. Burks and I will let you know if I learn more from him on this research as it seems to be more within reach than a $10,000 a year unproven prescription drug. The difference between 0.1mg of peanut protein, the allergen threshold for those with a severe peanut allergy, and 13 peanuts could the difference between life and death. It is reasonable to expect accidental exposure to 1mg of peanut protein or even a whole peanut, but I suspect it would be a lot less likely to be accidentally exposed to 13 peanuts before you realized it was happening!

Genetically Modified Peanuts:
Peanut interests have helped to fund the work of Peggy Ozias-Akins, a horticulture professor at the University of Georgia, Tifton. She wants to develop a plant whose peanuts are free of the three major protein allergens.

Screening the genetic structure of peanuts harvested on an experimental farm, Ozias-Akins is searching for ones with a defunct Ara h 2 gene, which is responsible for a protein that causes reactions in about 90 percent of patients with peanut allergy. When she finds plants with the defunct gene, she'll use them in a traditional breeding program to produce less-allergenic plants. She expects it will take at least three years to breed the plants and test them in animals.

Ozias-Akins's team also is trying to disable the Ara h 2 gene by modifying the peanut plant's genetic structure. She shoots cloned copies of the gene into a peanut, which can create a disabled gene that suppresses the function of the original one. Her team is growing plants with a disabled Ara h 2 gene in the greenhouse and testing whether the peanuts contain the allergy-causing protein.

Success is a long way off. Without the protein, other genes may compensate for its loss, making the new plants more, not less, allergenic than regular peanuts. As a result, any new genetically modified food product would have to go through animal testing and human clinical trials.

And even if Ozias-Akins gets there, it isn't clear that the world will embrace the results of her work. Says Duke's Burks, "If you take out all those proteins that cause allergic reactions to the peanut, then you no longer have a peanut."

While this is interesting, I will let you eat the first bag of genetically modified peanuts and wait to see what happens! I also am not sure that people need to eat peanuts this badly. While peanuts are a healthy source of protein, if you are training your daughter to avoid peanuts then you run the risk of confusing her by saying these modified peanuts (which probably look identical to allergen-laden peanuts) are fine while these other peanuts are bad. This is a similar line of caution that the former head of Anaphylaxis Canada expressed in reaction to the release of the peanut butter replacement, PeaButter. Seems to me that there is no market for this product unless allergenic peanuts are banned and we all eat the genetically modified variety.

While these projects are very interesting, what strikes me is the seemingly small aggregate pool of research on peanut allergy and food allergy as a whole. A 2002 study found only 33 food allergy research projects in the U.S. and less than $7M in total annual funding. I suspect that there is more happening now and I am trying to get better data to share with you. According to the WSJ article above, 'peanuts farmers and food processors have given $5.6M over the past decade to eight scientists, mainly for peanut-allergy work'.

I think that this area of research is fascinating. Parents of anaphylactic children should stay current on developments from these and other researchers. While sites and blogs (such as NoPeanuts) will have commentary and information, make sure you also ask your allergist or physician as they may have information that is even more current.


Rolski said...

That's fascinating. I especially like the idea of altering peanuts to be allergen free.

I'd be fascinated to know what you believe causes food allergy. Do you think it's increasing? I certainly seem to think we're hearing more and more about it. I wonder if something in our modern life, like children's early exposure to peanuts, might be behind an increase (if there is one.)

I had a bit of a grubby upbringing (on a farm) and I've certainly eaten more mud, dirt and peanuts as a child than most... But I've grown up allergy free. My wife, whose mother was obsessed with cleanliness, sniffles and sneezes at just about everything.

Just a random thought.

Loving your blogging.

NoPeanuts said...

It is a very interesting area. Perhaps mud and dirt are a vaccination ... hehe. On the one hand there is the 'what is happening for those who have the allergy' front and the other side of the equation, as you pointed out, is why is food allergy prevalence rising so quickly.

Stay tuned ... I intend to continue research on both fronts.

tanyaa said...

People who live in fear of their peanut allergy, anxiously avoiding numerous products and worrying that accidental exposure could cause a severe or even fatal reaction, may be cheered to learn that they may outgrow it.