Advances in specific immunotherapy give hope

Pollens lose their terror

Vienna, June 12, 2006. The grass pollen season peaks in the month of June in most European countries. Sufferers sneeze and cough, and fatigue is a debilitating symptom which impairs their quality of life. In addition to symptomatic drugs such as antihistamines and cortisone nasal sprays, specific immunotherapy (SIT) is a gold standard in the treatment of pollen allergies. The latest advances in this long-term effective treatment option are one of the main themes of the 25th Congress of the European Academy of Allergology and Clinical Immunology (EAACI), which takes place in Vienna from June 10 - 14, 2006. "The latest research data in specific immunotherapy may even hold out the hope of a cure for people with allergies," the president of the Vienna congress, Professor Rudolf Valenta said today.

Flowering grasses produce very large amounts of pollen whose function is to disseminate the plants' male genotype. People with a grass pollen allergy develop allergic rhinitis or asthma after breathing in the pollen particles, and face the prospect of months of symptoms every spring and summer. Highly allergenic rye blooms from May to June and from May to August is the flowering period for meadow grasses such as timothy, sweet vernal grass and cocksfoot. Many sufferers are allergic both to grasses and cereal crops as the pollen allergens of these plants are similar owing to their close botanic relationship.

Recombinant allergens now under clinical testing

SIT is the currently recognized gold standard for the treatment of pollen allergies. Patients undergoing SIT receive regular doses of extracts containing the allergy-triggering allergen until they can tolerate an allergic dose corresponding to exposure levels during the pollen season. The allergen extracts used for SIT today are manufactured from biological material and contain a mixture of potential allergens. They are standardized by a complex method to ensure that each batch contains the same amount of the desired major allergens.

An Austrian biotech company developed the first recombinant allergens several years ago. Recombinant allergens are similar to their natural counterparts but can be manufactured cost-effectively to give a reproducible and consistent quality. "Results from the first clinical trials testing recombinant grass or birch allergens in subjects with pollen allergy are now available," says Professor Rudolf Valenta, a pathophysiologist at the Medical University of Vienna. One of the studies shows that a recombinant major birch allergen (Bet v 1) is just as effective as purified natural birch allergen. Individuals who received two years of therapy reduced their symptoms and drug dose by more than 50 and 60 percent, respectively. "Impurities or the wrong dose may be the reason why immunotherapy doesn't work for all patients. Recombinant allergens with an unchanging composition and consistent quality might improve the response to treatment," says Valenta.

Grass tablet has market approval in Sweden

The usual procedure in specific immunotherapy is to inject the allergens. Allergologists have successfully used this subcutaneous immunotherapy method for more than a hundred years. Its efficacy is well documented in numerous placebo-controlled, double-blind trials. A sublingual SIT formulation has been available for more than ten years now. This method involves administering drops of the allergen solution under the tongue daily.

A tablet for specific immunotherapy successfully completed a rigorous clinical trial program this year. The tablet received marketing authorization in Sweden in March 2006 and will be available in the first European countries at the end of the year. This new treatment is given in the form of a matrix tablet containing standardized grass allergens. Patients who started immunotherapy with the tablets approximately ten weeks before the grass flowering season had significantly fewer symptoms than patients in the control group. The grass tablet improved allergy symptoms by 37 percent and more than doubled the number of symptom-free days.

Press Office EAACI Kongress 2006

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