Assistant

A year after bringing in its first major financing, privately held Circassia Ltd. closed an oversubscribed second round, adding £11 million (US$21.8 million) for expanding its portfolio of technologies aimed at regulating immune response and to accelerate ongoing clinical development programs in allergy.

To date, the Oxford, UK-based firm has raised about £17.5 million, including a £6 million funding round in January 2007 to support an upcoming Phase II study of its lead program in patients allergic to cat dander. The recent financing, which brings Circassia's cash balance to about £15 million, will "help us expand our portfolio and allow us to do more trials," said CEO Steve Harris, adding that it should "take us beyond the end of 2009."

The financing came "in a tough funding market," he said, crediting an investment syndicate that included new investors Goldman Sachs and Invesco Perpetual, along with existing investors Imperial Innovations and Lansdowne Partners.

Spun out of the Imperial College of London, Circassia was created to develop drugs for allergic rhinitis based on a technology that uses T-cell epitopes to desensitize the immune system.

Unlike more traditional immunotherapies, which are designed to dose patients with the whole antigen to build up tolerance - an approach that can produce serious side effects - Circassia's approach is to "take the T-cell epitopes from an antigen," isolated using the company's technology, and create a drug that "gives the therapeutic benefit without some of the side effects," Harris told BioWorld International.

The technologies identify short peptide sequences, usually 10 to 20 amino acids long, and those peptides then are selected for their ability to bind to multiple major histocompatibility Class II molecules on the surface of antigen-presenting cells.

Administration of the T-cell epitopes is designed to down-regulate the allergic response to the allergens from which the peptide originally was derived.

Importantly, because the peptides are kept short, they do not contain the B-cell epitopes, which are known to cross-link to IgE on the surface of mast cells. It's that cross-linking that causes anaphylactic reactions, Harris said.