Advair Ineffective in Some Children with Gene Variant: Study

British researchers have found that perhaps as many as 10% of children may not respond to Advair and other albuterol-based asthma treatments due to a gene variant, potentially increasing the risk of asthma attacks.

The gene variant Arg16 was identified as the likely reason many children do not respond to the albuterol asthma inhalers, which includes Advair, Serevent and Ventolin rescue inhalers. All three are popular inhalers sold in the United States by GlaxoSmithKline, PLC. In addition, the researchers found that children with the genetic variation were more likely to suffer an attack when taking the drugs on a daily basis than those who had the more common gene configuration.

Approximately 10% of children in the United Kingdom have the gene variant, and it is even more prevalent in other regions, such as India.

The results of the study, released this week by researchers from the University of Dundee and the Brighton and Sussex Medical School, suggest that doctors will eventually be able to perform a genetic test on children to look for the gene before prescribing an asthma medication. The study will be published by the American Academy of Allergy, Asthma and Immunology.

Researchers looked at 1,182 subjects from the ages of 3 to 22 years old from Scotland, finding that children with a single copy of the Arg16 gene variant had a 30% increase in the risk of having an asthma attack while taking Advair or Serevent over those who did not have the gene. Children who received a copy of the gene from both parents had a 70% increased risk. It is unclear how the gene affects adult usage of the inhalers.

The study also found that those with the genetic variant became more likely to have an asthma attack the more frequently the inhalers were used. However, the researchers cautioned that parents of children with asthma should not change how they medicate their children until more research can be done. They are uncertain whether those with the genetic variant are unresponsive to only albuterol and salmeterol, or whether they are unresponsive to a wide array of potential asthma medications.

Serevent and Advair side effects have been linked to an increased risk of severe asthma reactions in some users for some time, though the cause of the reactions remained a mystery. In 2006, the FDA made Glaxo place a “black box” warning on Advair and Serevent, indicating that the drugs could increase the risk of asthma-related death. In 2007, a panel of advisors to the FDA suggested that even more specific warnings needed to be added to the labels in addition to the black box warning. The black box warning is the strongest warning that can be placed on a prescription medication.

Asthma affects about 9% of children in the U.S., or about 6.5 million children. Advair and Serevent are GlaxoSmithKline’s best-selling products. Advair generated $7.9 billion in sales in 2008, and Serevent sales topped $639 million.