Imagine constantly worrying that something you eat is going to cause your throat to swell shut or your heart to stop beating. That’s the reality people with severe peanut allergies must live with every day, because their bodies launch out-of-control immune responses against even a trace of peanut protein.
But now, relief may be on the horizon. A phase 3 clinical trial by pharmaceutical company Aimmune Therapeutics shows that gradual and methodical exposure to purified peanut protein can train the body to drastically tone down the reaction. After one year of daily treatment with the company’s peanut protein-filled capsules, currently called AR101, study participants could safely tolerate 30 times more allergen than they could before the trial began.
The trial included 496 children aged 4 to 17 with allergies so severe that they could not ingest more than 30 milligrams of peanut protein without experiencing moderate to highly dangerous effects. For reference, one peanut contains 250 to 350 milligrams of peanut protein.
Half of the children were given daily AR101 pills of increasing protein doses until they reached 300 milligrams at week 22. They then remained on that dose for six months. The other half of the group received placebo pills, and neither the patients nor the doctors knew who got what until the study ended.
After about 48 weeks, peanut protein tolerance was tested with a food challenge: Children were given increasing doses of peanut protein 20 to 30 minutes apart while being closely monitored. The amount at which their symptoms switched from nonexistent/mild to moderate was considered their safe limit.
Exceeding the researchers’ expectations, 67.2 percent of AR101 patients could tolerate single doses of up to 600 milligrams, or 1,043 milligrams total over no more than 2.5 hours. Only 4 percent of placebo patients achieved this. Moreover, 50.3 percent of AR101 patients could handle the maximum tested amount, 1,000 milligrams of peanut protein (2,043 milligrams over 3 hours), compared with 2.4 percent of placebo children.
“It’s great to have patients go from managing to tolerate at most the amount of peanut protein in a tenth of a peanut without reacting to successfully eating the equivalent of between two to four peanuts with nothing more than mild, transient symptoms, if any at all,” said study leader Dr A. Wesley Burks in a statement.
Currently, patients who received AR101 continue to take pills of varying doses so that their immune systems remain acclimated, and those who were given placebo have been allowed to take the actual drug. Should their ongoing follow-up and future studies (including some with adults) go as well as this trial, AR101 could soon be the first food allergy prevention drug ever approved. And although this type of therapy can’t erase someone’s peanut allergy completely, taking AR101 may free them from harm during accidental exposures.