Aimmune Therapeutics says the US Food and Drug Administration has approved its drug to reduce, and potentially eliminate, allergic reactions to peanuts in children aged 4 to 17, pricing it at $US890 per month ($1,330).

The treatment, called AR101 and to be sold under the brand name Palforzia, was designed to gradually reduce sensitivity to peanuts by exposing patients to a highly refined version of peanut flour over several months.

The oral drug will be the first in the market to offer relief from peanut allergy symptoms for those who previously had to avoid all contact with peanuts in any form or risk a reaction requiring emergency treatment with an epipen or another epinephrine shot.

The goal, the company says, is to get allergic children and teens to the point where accidental exposure to small amounts of peanuts do not trigger a potentially life-threatening immune response.

Some 1.6 million US children aged 4 to 17 live with peanut allergies, Aimmune says, creating an opportunity for peak annual sales in excess of $US1 billion.

Peanut allergies are the leading cause of death from food-induced allergic reactions in the United States, with symptoms ranging from red, swollen skin to potentially deadly airway constriction.

The FDA-approved label for Palforzia includes a warning of its potential to trigger a possibly dangerous allergic response.

Aimmune said each dose increase will be done under the supervision of an allergist who is prepared to treat any allergic reactions that arise.

The list price of a drug is not necessarily what patients will actually pay, with out-of-pocket costs varying based on the duration of the treatment and individual healthcare plans.

The approval comes months after an independent panel of experts to the FDA backed the allergy therapy but raised concerns about the risk of severe allergic reactions it poses to young patients.

Palforzia may soon face competition from French drug maker DBV Technologies, which has filed for US approval of a once-daily skin patch to reduce sensitivity to peanut exposure.

The FDA is expected to make its approval decision for DBV’s Viaskin Peanut patch by August 2020.