CIR.L Regulatory News (CIR)

-- Circassia Announces Results from House Dust Mite Allergy Treatment Phase IIb Two-Year Follow-up Study --

Oxford, UK - 13 June 2014:Circassia Pharmaceuticals plc ("Circassia" or "the Company") (LSE: CIR), a clinical-stage specialty biopharmaceutical company, today announces positive top-line results from a two-year follow-up of a phase IIb clinical study of HDM-SPIRE, a house dust mite allergy product candidate based on Circassia's proprietary ToleroMune® platform technology.

The phase IIb two-year follow-up study (TH002A) enrolled 72 subjects who had previously received either placebo or one of two 12-nmol dose regimens as part of the original phase IIb study (TH002) which randomised 172 subjects. One year on from the last assessment point, and two years after starting treatment with HDM-SPIRE or placebo, investigators reassessed patients' allergy symptoms when exposed to house dust mite allergen in an environmental exposure chamber. Improvements in nasal and ocular symptoms were measured using the Total Rhinoconjunctivitis Symptom Score (TRSS) on the second and third days of the three-day house dust mite allergen challenge.

Highlights from phase IIb two-year follow-up study

· Improvements in TRSS compared to placebo in the 4 x 12-nmol treatment group1 observed at two years were equivalent to the reductions in the same group of subjects observed at one year;

· As seen in previous SPIRE clinical studies, subjects with more severe allergy symptoms demonstrated a greater treatment effect after receiving HDM-SPIRE compared to placebo;

· When data from all three days of the house dust mite allergen challenge were included, improvements in TRSS compared to placebo in the 4 x 12-nmol treatment group1 were even greater when compared to the second and third days alone;

· HDM-SPIRE continues to be well-tolerated with no late-onset safety concerns identified; and

· These encouraging data will be used to inform the wider HDM-SPIRE clinical programme.

1. Subjects in this treatment group received a short course of four 12-nmol doses of HDM-SPIRE over 12 weeks.

Given that the two-year follow-up study enrolled a smaller number of subjects than the original treatment study, it was not powered to deliver statistically significant results. Circassia intends to present these data in due course as part of the Company's wider scientific publication programme.

Steve Harris, Circassia's Chief Executive, said: "These encouraging trends suggest that our short-course house dust mite allergy treatment has lasting effects two years on with no further injections. Results from long-term follow-up studies, even with smaller patient numbers, are invaluable for informing the design of future clinical studies across our portfolio of product candidates. We believe our short-course SPIRE treatments could offer significant benefits and, having completed 18 clinical studies, our late-stage data set continues to underline our confidence in the ToleroMune® platform technology."

Original phase IIb study design

The double-blind, randomised phase IIb trial (TH002) was conducted in Toronto, Canada, where 172 volunteers with confirmed house dust mite allergy received one of four treatment regimens or placebo. Investigators measured patients' allergy symptoms when exposed to house dust mite allergens at baseline and during the 12-month study. As announced in September 2013, those who received a short course of four 12-nmol doses over 12 weeks had a significant improvement in their symptoms one year after starting the treatment compared with those on placebo (p=0.02). All treatment regimens were well tolerated, with a safety profile similar to placebo.

Next steps in HDM-SPIRE clinical programme

Building on the encouraging data generated from the HDM-SPIRE clinical programme to date, Circassia plans to initiate a randomised, double-blind, placebo-controlled phase IIb field study (TH005) to: confirm the efficacy of a short course of four 12-nmol doses seen in the first phase IIb study; evaluate two courses of HDM-SPIRE (eight doses); and evaluate the safety and efficacy of a higher 20-nmol dose of HDM-SPIRE. Having agreed the design with the US Food and Drug Administration (FDA) in May 2014, this study is on track to start in Q4 2014. A phase II controlled asthmatic safety study (TH004) in 30 subjects is also due to report in H2 2014.

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Notes to editors

1. Circassia

Circassia is a specialty biopharmaceutical company focused on the development and commercialisation of a range of immunotherapy product candidates for the treatment of allergy. Established in 2006, the Company has used its innovative proprietary technology, ToleroMune® to develop a new class of allergy therapies, Synthetic Peptide Immuno-Regulatory Epitopes (SPIREs), which Circassia believes represents a step change to a new generation of allergy treatment. The Company's portfolio of product candidates is designed to treat a broad range of seasonal and perennial allergies. The lead product candidate Cat-SPIRE, a new treatment for cat allergy, is currently in phase III development and three other product candidates have completed phase IIb clinical studies. As Circassia continues to grow, the Company remains focused on its founding principle - a commitment to improving patients' lives by controlling immune responses. Further information is available at: www.circassia.co.uk.

2. House dust mite allergy

House dust mites are found widely throughout homes, in bedding, carpets, soft furnishings and clothing. Allergy to proteins in the dust mites' droppings is extremely common, and often associated with asthma. In the USA and Europe, approximately one-in-four people are sensitised to house dust mites, with more people having allergic responses to this common allergen than to any other. House dust mite allergy is a perennial condition that can impact sufferers' education, work, quality of life and social activities.

3. ToleroMune® platform technology

Circassia's novel, proprietary ToleroMune® platform technology uses rationally-designed molecules identified from common allergens (Synthetic Peptide Immuno-Regulatory Epitopes; SPIREs) to generate regulatory T cells to control allergic responses and induce immune tolerance. Circassia has successfully completed a number of phase II studies with its house dust mite, ragweed and grass allergy product candidates, and its cat allergy treatment is currently in phase III development.

4. Allergy market

Allergic rhinitis (AR) is a global healthcare problem with an estimated 400 million people suffering worldwide. Direct costs for AR increased from $ 2.7 billion in 1995 to $7.3 billion in 2002 in the USA alone. With indirect costs estimated at $4.28 billion, this gives a total cost of $11.58 billion in 2002 (source: WAO, White Book on Allergy, 2011). Clinical results to date show that short courses of Circassia's SPIRE allergy treatments can greatly reduce patients' allergic responses and improve symptoms over long periods, while proving extremely well-tolerated. As a result, SPIRE treatments have the potential to offer major clinical benefits compared with existing therapies.