Allergy vaccine firm Circassia raised £60 million (about $97.72 million). The funding will be given in two tranches over two years. Imperial Innovations led the round, committing to invest £15 million.
Innovations‘ first installment will be £6.3 million. The balance will be paid subject to the achievement of certain milestones. Following the payment of the first tranche, Innovations will hold 18.4% of the equity. Circassia reports that to date it has obtained £93.1 million through four investment rounds, with Innovations contributing £13.8 million in total.
The new investment will fund Circassia's Phase III development programs for cat and ragweed allergy therapies, completion of Phase II testing for house dust mite and grass allergy T-cell vaccines, and advancement of development programs of three additional allergy therapies as well as Circassia’s recently acquired psoriasis treatment.
In February Circassia took over the worldwide development and commercialization rights to Airmid’s preclinical-stage topical candidate for the treatment of psoriasis and atopic dermatitis. PAP-1 is a small molecule Kv1.3 calcium channel blocker derived from the medicinal plant Ruta graveolens, which reportedly acts on effector memory T cells but leaves naive and central memory T cells intact. Preclinical studies have demonstrated the activity of topically applied PAP-1 in psoriasis and atopic dermatitis models, according to Circassia.
The company’s cat allergy candidate is the furthest along in development. Positive Phase II results were reported in February. In November 2010, positive data was reported from a Phase II trial with the house dust mite allergy candidate, and the final Phase II study with a ragweed allergy ToleroMune therapy was initiated. Data from a Phase II grass allergy candidate is expected this year. In the research stage are vaccines against birch, alternaria, Japanese cedar, and dog.
Circassia’s T-cell vaccines are based on its ToleroMune® technology. The firm has operations in the U.K. and Canada and says that it is broadening its pipeline beyond allergy into other therapeutic areas that hinge on control of the immune system.
ToleroMune identifies short peptide sequences, typically 10 to 20 amino acids long, from the allergen proteins that are responsible for causing allergic reactions in sufferers. These peptides are selected for their ability to bind promiscuously to multiple major histocompatibility class II (MHC Class II) molecules on the surface of antigen-presenting cells.
Circassia explains that its peptide vaccines comprise short sequences of amino acids that can be chemically synthesized and readily standardized. Administration of these epitopes induces regulatory T-cells, which downregulate the T-cell, B-cell, and mast-cell components of the allergic response to the allergens from which the peptide was originally derived.
As the peptides selected by ToleroMune are linear, they do not contain B-cell epitopes, which are present in whole allergens and cause the cross-linking of IgE on the surface of mast cells that is associated with itchy eyes, runny nose, and asthmatic responses, according to the company. Cross-linking of IgE can also cause anaphylactic-type reactions.