Circassia Limited Achieves Positive Phase II Clinical Results With Ragweed Allergy T-Cell Vaccine Results Mark Third Successful Phase II Study With ToleroMune(R) T-Cell Vaccines

OXFORD, England, February 12 /PRNewswire/ -- Circassia Ltd, a specialty biopharmaceutical company focused on allergy, today announced that its ToleroMune(R) 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% higher than baseline. In contrast, the optimal ToleroMune T-cell vaccine regime reversed this seasonal increase and reduced it by a further 47% 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."

About Circassia's allergy T-cell vaccines

Circassia's range of allergy T-cell vaccines is based on its proprietary ToleroMune(R) technology. This technology utilises allergen epitopes to generate regulatory T cells that suppress allergic immune responses. Clinical results with Circassia's cat allergy T-cell vaccine show that short treatment regimes can greatly reduce patients' symptoms, without the need for adjuvants or other immune stimulators, while proving extremely well tolerated. As a result, the company's allergy T-cell vaccines offer major potential clinical benefits compared with existing therapies, and consequently have significant market opportunities. Over 150 million people suffer from allergic rhinitis in the US and Europe, and the current treatment market is approximately $12 billion per year.

ToleroMune technology has additional potential regulatory and supply chain benefits. The short peptides utilised in Circassia's vaccines are manufactured chemically, in contrast to existing allergen immunotherapies, which are purified from natural sources. Circassia's approach applies the chemistry, manufacturing and control standards associated with conventional pharmaceuticals to its allergy T-cell vaccines. This fits with changes in the European regulatory environment, where authorities are increasingly treating allergen immunotherapies as pharmaceutical products, and requiring elimination of the batch-to-batch potency variability that is an intrinsic feature of many current treatments.

About Circassia

Circassia has a highly experienced management team with a proven track record in product development and commercialisation. Having successfully completed three fundraising rounds the company is backed by a syndicate of world-class venture capital and institutional investors, including Imperial Innovations, Invesco Perpetual, Goldman Sachs and Lansdowne Partners.

CONTACT: Contacts: Steve Harris, CEO, Circassia, Tel: +44(0)1865-784574,
Rob Budge, RJB Communications, Tel: +44(0)1865-760969, Mobile:
+44(0)7710-741241