Positive Results for Xolair For Food Allergy Protection. But Will the Protection Last?

After the FDA approval approved Xolair (omalizumab) for protection against food allergies a little more than a week ago, results of the phase 3 placebo-controlled trial that was the basis for that approval were published today in the New England Journal of Medicine (NEJM) and presented at the American Academy of Allergy, Asthma and Immunology annual meeting in Washington.

Xolair is being heralded as an important advance for children and adolescents with food allergies. By lowering the risk of serious allergic reactions, the drug may reduce fear and anxiety about accidental exposure to foods that trigger strong allergic reactions.

Approximately two-thirds (67%, 79 of 118) of the participants in the OUtMATCH trial who were treated with Xolair injections for between 16 and 20 weeks met the trial’s primary endpoint, which was consumption of 600 milligrams (mg) of peanut protein (about the amount in three to four peanuts) without moderate or severe allergic reaction (or combination of mild reactions). The reactions included hives, swelling, itching, throat tightness and abdominal pain, nausea or vomiting.

In comparison, just 7% (4 of 59) of the those randomly assigned to the placebo group could eat the 600 mg of peanut protein without a significant allergic reaction.

Robert A. Wood, M.D.

Study participants were also “challenged” with consumption of 1,000 mg of cashew, egg and milk protein after the treatment period. The results reported by lead author Robert A. Wood, M.D., of a professor of pediatrics at Johns Hopkins, and his colleagues reported that there was there was less protection from an allergic reaction to cashew protein (41%, 28 of 68 study participants) compared with protection to a reaction from egg protein (67%, 34 of 51 study participants) and milk (66%, 27 of 41 study participants).

Gary W.K. Wong, M.D.

In a two-page editorial in the New England Journal of Medicine accompanying and commenting on the Xolair study, Gary W.K. Wong, M.D., of the Prince of Wales Hospital of the Chinese University of Hong Kong, said that results from the open-label, 24-week extension of the main trial raises questions about how durable the protective effects of Xolair are.

“Persons who opt to receive omalizumab must be informed that the possible protection will most likely disappear after omalizumab treatment is stopped,” wrote Wong, who also posed as a question whether people who have a history of mild reactions will decide to get Xolair injections on regular basis instead of taking the usual approach to peanut and other food allergies that involves avoiding those foods.

Xolair is administered as subcutaneous injection and packaged in prefilled syringes for home use. Children and adolescents are the prime patient population; the median age of the participants in this study who were randomized to treatment with Xolair was 6.5 years. In the placebo group it was 7.

Wood and his colleagues drew an inference from the extension trial that was opposite from Wong’s. “Additional treatment for 24 weeks in the open-label extension trial appeared to show the durability of the response, with most participants showing stable or increased challenge thresholds,” they wrote in the discussion section of the NEJM paper where authors comment about the results they have reported.

In the results section, Wood and his colleagues reported that the challenge thresholds — the amount of the peanut protein that produced a notable allergic reaction — remained the same after the extension period for 45% of the participants, increased for 34% and decreased for 21%.

Xolair (pronounced ZOHL-air) is monoclonal antibody that binds to immunoglobulin E (IgE), an antibody type that plays a critical role in triggering allergic reactions. The FDA originally approved Xolair in 2003 as treatment for moderate to severe persistent allergic asthma. The drug regulator subsequently added approvals for use as a treatment for chronic spontaneous urticaria (urticaria is commonly known as hives) and chronic rhinosinusitis with nasal polyps in certain patients.

The FDA announced the approval of Xolair for food allergy protection on Feb. 16.

“Patients who take Xolair must continue to avoid foods they are allergic to,” the FDA said in the news release about that approval. The news release also noted that that Xolair is intended for repeated use to reduce the risk of allergic reactions and is not approved for the immediate emergency treatment of allergic reactions, including anaphylaxis

The estimated list price for Xolair for food allergy protection will range from approximately $2,900 for children and $5,000 for adults each month, according to a spokesperson for Genentech, which developed and promotes Xolair in the U.S. with Novartis. The Genentech spokesperson said in an email that the actual cost paid by most patients is usually lower those amounts because of insurance coverage and financial assistance programs.