Circassia completes recruitment for cat allergy treatment pivotal phase III study

Circassia Pharmaceuticals plc, a specialty biopharmaceutical company focused on allergy, has announced that it has completed recruitment into the pivotal phase III study of its cat allergy treatment, Cat-SPIRE. When recruitment closed on 31 December 2014, 1,409 subjects had been randomised into the study. The total recruited exceeds the minimum target of 1,182, and includes an additional 91 subjects enrolled at centres in Russia to support a potential filing in this significant market. The study is progressing as planned, and the Company remains on track to report the results in H1 2016.

Steve Harris, Circassia's Chief Executive, said: "Our phase III Cat-SPIRE study is designed to efficiently assess our treatment in subjects who would benefit most from an effective new therapy. The team has made great progress in completing enrolment as planned into this international field study. We continue to be well placed to meet our timelines to complete the study in H1 2016, and, subject to the results, to file for regulatory approval later the same year."

Phase III study design (CP007; or CATALYST) The Cat-SPIRE study design follows guidance from the FDA, EMA and Health Canada, who advised that a single pivotal phase III trial is sufficient for registration. The study, which is being conducted under the name CATALYST (an abbreviation of Cat Allergy Study), is powered to meet each of the regulators' statistical requirements. The double-blind, randomised, placebo-controlled, multi-centre field study has enrolled 1,409 cat allergic subjects aged 12 to 65 years with a cat at home and moderate or severe allergy symptoms (mean Total Rhinoconjunctivitis Symptom Score (TRSS) ≥ 10). The study allows inclusion of subjects with controlled asthma after an earlier clinical trial showed Cat-SPIRE to be safe and well tolerated in this group.

The study is ongoing in approximately 160 centres across the United States, Canada, six European countries and Russia, and is assessing a single course and two sequential courses of Cat-SPIRE, each of 4 x 6 nmol doses administered over 12 weeks. The primary efficacy endpoint is a comparison of the change in combined TRSS and rescue medication use scores one year after the start of treatment versus placebo. In an earlier phase IIb study, subjects who received 4 x 6 nmol doses of Cat-SPIRE had a statistically significant improvement in TRSS one year after beginning treatment compared with placebo (p=0.01).

Cat allergy

Cat allergy is a common condition, with skin prick testing suggesting it is the third most prevalent allergy in Europe and the sixth most prevalent in the United States. In Europe, approximately 8 - 10% of the population is estimated to be sensitised to cat allergens, while a national survey in the US estimated 17% of the population is sensitised.

Circassia's candidate cat allergy treatment, Cat-SPIRE, contains a mixture of seven synthetically produced small peptides, identified from the main allergen responsible for cat allergy (Fel d 1) using the Company's proprietary ToleroMune® technology. The treatment is designed to generate a regulatory T-cell response to induce tolerance to naturally occurring cat allergen.