Durable Hay Fever Suppression May Require Three Years of Immunotherapy

Immunotherapy that exposes hay-fever patients to increasing amounts of grass pollen over time can be an effective way to reduce severe allergic symptoms in the long term. But in a new study published today in the journal JAMA, results from the ITN GRASS trial demonstrate that a two-year course of treatment is not enough to achieve lasting effects, bolstering previous findings that more time is needed taking the medication to get lasting benefit.

While there is currently no cure for hay fever, a number of over the counter medications are available, such as nasal sprays and antihistamine tablets. Patients with more severe symptoms can be treated with immunotherapy, using a similar approach to the one trialled in children with peanut allergies. By exposing their immune system to grass pollen extracts over time they are able to build up their resistance, either through injections or a pill containing pollen extract.

In the GRASS Study, led by Professor Stephen Durham from the National Heart and Lung Institute at Imperial College, London, UK, researchers tested the effectiveness of two immunotherapies that use grass pollen extract: an injection and a pill taken under the tongue. In the first head to head trial of the two therapies, 106 patients with moderate to severe hay fever were administered either the daily oral treatment, regular injections or a placebo.

The study set out to see if a two-year treatment could achieve the same long-lasting benefits to patients as seen with three-years of immunotherapy, potentially leading to clinical cost savings. After a two year course of treatment, the results showed that both therapies were effective at tackling symptoms, with patients reporting a dramatic improvement in their quality of life.  However, one year after patients had stopped taking the medication the effects were no better than the placebo group.