Circassia Ltd, a specialty biopharmaceutical company focused on allergy, announced positive results from a recently completed phase-II clinical study of its ToleroMune cat allergy therapy, which successfully identified the optimal dosing regimens to progress into late-stage development. The clinical trial, which was the first of its kind in the field of cat allergy immunotherapy, showed that Circassia's ToleroMune treatment was extremely well tolerated and greatly reduced sufferers' symptoms.

Circassia conducted the double-blind study in Canada, where 121 subjects with confirmed cat allergies were randomised to receive placebo or one of four different treatment regimes with standardised doses of ToleroMune. The volunteers were exposed to cat allergens (aerosolised dander) in an environmental exposure chamber for three hours each day on four consecutive days, both before and after treatment. At set time points the subjects scored their ocular and nasal symptoms to allow investigators to measure the effect of the ToleroMune treatment. This is the first trial of a cat allergy immunotherapy to use this validated approach.

The study's results demonstrate that ToleroMune therapy can dramatically reduce both nasal and ocular allergy symptom levels, and that the treatment effect grows as the duration of exposure increases and symptoms are at their greatest. The optimal regimen decreased total symptom scores by 67 per cent compared with placebo. Throughout the study ToleroMune treatment was extremely well tolerated, with a safety profile similar to placebo. This contrasts with many traditional immunotherapies, which are associated with a range of local tolerability issues and sometimes severe and even life-threatening adverse events.

"These positive phase-II results are extremely important for Circassia as they identify the optimal treatment regime to move into the final stages of development for our cat allergy therapy, and will prove invaluable as we progress our broader portfolio of ToleroMune products," said Steve Harris, Circassia's CEO. "We are particularly pleased that the ToleroMune treatment achieved such a marked improvement in ocular symptoms, which can be a particular problem in cat allergy. As well as benefiting patients, this effect scientifically validates the ToleroMune approach and its novel focus on generating regulatory T cells to shut down this type of IgE-mediated allergic response."