Common allergies including asthma and allergic rhinitis (encompassing hay fever and dust and pet allergies) affect an estimated 30% of the population of developed countries, incurring a global drugs bill in excess of £6 billion. Currently treatment is almost exclusively aimed at tackling the symptoms rather than curing the actual underlying disease. For those affected, that means a lifetime of treatments ‒ often with products that carry a risk of unwanted side-effects.

In 1995 Imperial College researchers Professor Barry Kay and Dr Mark Larché were investigating the role of white blood cells called T Cells in allergies. T Cells along with their B Cell counterparts are the gatekeepers of the bodies’ immune system, identifying and reacting to infections and agents deemed to be ‘non-self’.

The researchers found that in ‘sensitised’ individuals with allergies, when part of the allergen called a peptide epitope encounters T Cells it appears provoke one of two responses ‒ an allergic reaction or complete tolerance to the whole allergen particle. Which of these two pathways are taken seems to depend on several complex factors including the binding properties of the peptides, the route of administration, dose and the interval between doses.

Seeking to exploit this principle, Kay and Larché set out to develop a safe and effective synthetic peptide vaccine that would lead to allergen tolerance.

They filed the first of many successful patent applications for ‘use of peptides for desensitisation to antigens’ in March 1997. In December 1998 Circassia Limited, an Imperial College spin-out was incorporated with Professor Kay and Dr Larché as co-founders.

Testing, testing

What followed in the ensuing 15 years was a period of extensive testing of the prototype vaccine technology ‒ firstly in bronchoalveolar cell biopsies, then in an animal model of peptide immunotherapy and eventually early clinical trials in patients.

With promising results, Circassia attracted tens of millions of pounds in several rounds of investment and began to focus on further developing its ToleroMune vaccine for cat and ragweed (grass) allergies.

Final push

In March 2014 Circassia floated on the London Stock Exchange, raising £200 million in what was the largest initial public offering for a biotech company in decades. The share price valued the company at around £580 million. At the time of writing in December 2014, Circassia finished recruiting for its final Phase III cat allergy trial with first results expected in early 2016. Meanwhile the ragweed Phase II trial has shown promising results after three pollen seasons. The company is also looking to apply its vaccine technology to patients with controlled asthma.

Overall, Circassia’s therapies have the very real potential to become the standard treatment for allergy prevention and significantly reduce the burden of burden of disease on a global scale.