* Allergy firm tests European market for larger biotech IPOs
* Follows boom in biotech offerings in United States
* Funds to help bring cat allergy vaccine to market
By Paul Sandle
LONDON, Feb 6 (Reuters) - Circassia, a company developingallergy treatments based on a discovery by scientists atImperial College in London, aims to raise about 175 millionpounds ($285 million) of new funds in one of Europe's biggestbiotechnology IPOs.
The stock market debut in London will help to bring its catallergy vaccine to market.
Chief executive and co-founder Steve Harris said theproceeds of the flotation in London would also support thefirm's programmes in other common allergies such as house dustmites, grass and ragweed.
Biotechnology has proven to be a hot investment in the pastyear in the United States, triggering dozens of initial publicofferings (IPOs) - but the sector has been slow to catch fire inEurope.
That makes Circassia an important test of investor appetitefor larger biotech offerings, according to Robin Davison, ananalyst at Edison.
A successful flotation could encourage more biotech firms toraise money in London rather than crossing the Atlantic, asDutch gene therapy company uniQure did this week forits IPO.
Circassia was formed in 2006 to commercialise innovativetechnology developed at Imperial College, which synthesises partof the allergens that cause reactions in sufferers.
The approach is quicker and has none of the side effects oftreatments that expose sufferers to small samples of theallergen to build up resistance, Harris said on Thursday.
"We are not based on whole allergen-immunotherapy," he said.
"We take T-cell epitopes that are identified from the wholeallergen, we make them synthetically, and we give fourinjections that treat the underlying disease rather thaninjections over weeks, months or years."
The company had already received 105 million pounds offunding from investors including Imperial Innovations,which holds just under 20 percent, Goldman Sachs, InvescoPerpetual and Lansdowne Partners, he said.
They had indicated they would support the fundraising, hesaid. A small number of existing shares could also be includedin the offer, he added.
The company has conducted over 15 clinical studies for itsprogrammes, he said, and the results of late-stage trials in catallergy in Europe, Canada and the United States were expected inthe first half of 2016.
It has also demonstrated proof-of-concept for treatments forhouse-dust mite, grass and ragweed allergies, common conditionsthat affect millions of people.
"Over the course of the last six months, we've had someexcellent data on our other programmes and we are now in aposition to push forward on multiple fronts with a lot ofconfidence," Harris said.
JP Morgan Cazenove and Peel Hunt are the joint book runnerson the offer.