Circassia Ltd, a specialty biopharmaceutical company focused on allergy, announced that its ToleroMune ragweed allergy T-cell vaccine achieved positive results in a recently completed phase-II clinical trial. Ragweed allergy is particularly common in America, where it affects approximately 25% of the population. Circassia's latest clinical results follow two earlier successful phase-II studies with the company's T-cell vaccine against cat allergy. The company has three additional phase-II trials ongoing, targeting house dust mite and cat allergies, and plans to initiate three further studies in the coming months, extending the portfolio into the field of grass allergy.

The results from Circassia's latest clinical study demonstrate that four doses of the ToleroMune T-cell vaccine greatly improved the allergic responses measured in the trial. The efficacy endpoints, which included the early phase skin response to a challenge dose of ragweed allergen, were measured both before and after the ragweed season. This response, which is commonly used by allergists to assess allergic status, showed a characteristic increase in the placebo group by the end of the ragweed season, resulting in values 37 per cent higher than baseline. In contrast, the optimal ToleroMune T-cell vaccine regime reversed this seasonal increase and reduced it by a further 47 per cent compared with the pre-ragweed season baseline. Throughout the study, the ToleroMune vaccines were safe and well tolerated, with a treatment-related safety profile similar to placebo.

"These highly encouraging clinical results further validate our unique T-cell vaccine approach to allergy therapy. Our ToleroMune technology has now shown its potential to address both ragweed and cat allergies, and we hope to extend this product range when we receive the results of our ongoing study in house dust mite allergy later this year," said Steve Harris, Circassia's CEO. "With three phase-II studies now complete, our growing clinical database demonstrates the true potential of our ToleroMune T-cell vaccines. Unlike current immunotherapies, which require increasing doses over a number of months and several years of maintenance, ToleroMune therapy is short and simple, and minimises the risk of the severe and sometimes life-threatening side effects associated with many existing treatments."