Advisers to the Food and Drug Administration voted Friday to recommend approval of a first-of-its-kind peanut allergy treatment, which can desensitize children to potentially life-threatening allergies. If the agency follows through and approves the drug, it would be the first of what's expected to be a wave of new food allergy treatments that prevent a reaction, rather than simply treat one after the fact.

The advisory committee voted 7-2 that the drug, called Palforzia, works and 8-1 that it is safe. The deliberations are not binding, but the agency usually follows the recommendations of advisory committees. The drug would be required to carry a black box warning, the agency's most serious red flag that a drug can be a hazard to patients and would also be subject to an additional safety program. That's because Palforzia carries a risk of side effects, including an increase in allergic reactions and the need for injections of epinephrine with a pen device to quell systemic responses.

After a year of treatment with Palforzia, most children in a large trial were able to tolerate the equivalent of two peanuts. The therapy is not a cure; people will still need to avoid peanuts and carry emergency medication.

Palforzia, which is made by biotech company Aimmune Therapeutics, is aimed at reducing reactions when people are inadvertently exposed to peanuts, for example when eating a food that has been cross-contaminated. The company is seeking approval for administering the drug to children ages 4 to 17.

"For a family with high anxiety and a significant burden of anxiety and fear from living with peanut allergy, this might give that extra buffer of safety," said Marcus Shaker, a pediatric allergist at Dartmouth's Geisel School of Medicine, who was not involved with the trial. "They're still going to need to strictly avoid peanuts, but [this will help] to let go of some of the fear they may have."

The committee's deliberations will be closely watched, not only because it represents the first treatment for peanut allergy but also because the therapy - essentially a capsule of pharmaceutical-grade peanut protein - is expected to be the first in a new generation of food allergy therapies that work by gradually increasing people's exposure to the allergen.

Despite the excitement, allergists said the treatment may not be appropriate for some patients. Treatment requires repeated office visits and regularly taking a drug that can trigger, in the short term, the very side effects it aims to prevent.

In a large trial of 551 people, including 496 children, one in 10 of the people who received the drug dropped out because of adverse events, which included abdominal pain, vomiting and systemic allergic reactions. In that trial, 14 percent of patients taking the drug had to use an epinephrine pen to quell a severe reaction - more than twice the rate of those taking a placebo.

"I think it may not be for every patient with peanut allergy," said Hemant Sharma, chief of the division of allergy and immunology at Children's National Medical Center, who was involved in the trial. "What I will be doing, and many of us as allergists will be doing, is having careful conversations with our patients about whether this is something they're even interested in doing."

Shaker said that it remains to be seen whether patients will accept the increased allergic reactions for the protection it confers against accidental exposure.

"I think we need more data on what it's going to mean to patients and how it's going to change their level of risk perception and change their quality of life," Shaker said. He said the drug is "a little bittersweet for everybody. Everyone's happy to see something happening, and yet it's not what we asked for from Santa Claus."

Some physicians already use escalating doses of inexpensive peanut flour to desensitize allergies, but federal approval of a drug would probably be covered by insurance and expand use of the approach. Aimmune scientists say that an approved drug will also eliminate uncertainties about dosing when using off-the-shelf peanut flour.

Steve Tilles, senior director of medical affairs at Aimmune, said that it is not yet known how long people will need to stay on the drug, but he is hopeful that after a few years of treatment, people could discontinue it while remaining desensitized to peanuts.

Aimmune is also working on a therapy for egg allergies and tree nuts. Other researchers are working on a skin patch to treat peanut allergies or delivering a drug under the tongue.

Aimmune did not provide information on how much the drug would cost, but a recent analysis by ICER, a watchdog organization that focuses on drug pricing, concluded there was insufficient evidence that the drug was more beneficial than simply avoiding peanuts.