UPDATE 1-Antigenics seeks EU approval for cancer vaccine

* Antigenics seeks EU approval for Oncophage in kidney cancer * If approved, will be EU's first therapeutic cancer vaccine * Further studies likely needed after conditional approval (Updates with further details, background)

LONDON, Oct 22 (Reuters) - Antigenics Inc (AGEN.O) has submitted its Oncophage cancer vaccine for conditional approval in Europe in a move that could open new markets for the product, which is currently only cleared for use in Russia.

If approved, Oncophage will be the first therapeutic cancer vaccine to receive a marketing licence in the European Union.

The New York-based biotechnology company, which has been developing the vaccine for more than a decade, said on Wednesday it had sought conditional approval from the European Medicines Agency to market the vaccine for kidney cancer.

Europe's conditional approval system, introduced two years ago, means regulators can approve drugs while simultaneously requesting additional follow-up of patients or further clinical studies.

If at the end of the trial period the drugs agency is not satisfied, it can pull a product from the market.

In an unusual move, the Russian authorities in April became the first in the world to appove Oncophage, even though it failed a late-stage clinical trial.

The Russian green light was based on a subset of data from the Phase III study which showed some patients -- those whose cancer was least likely to recur following surgery -- lived longer without their disease recurring when given Oncophage.

Antigenics believes findings from this and 14 other smaller studies should also support European approval for Oncophage as a treatment for earlier-stage, localised kidney cancer.

The European review process could take 12 to 18 months.

Oncophage is designed to reprogramme a patient's immune system to target cancer cells from a specific tumour.

The company takes tissue from a tumour following surgery, extracts proteins it says activate the immune system and then injects the enriched proteins back into the body through the skin.

Unlike a vaccine such as Merck & Co's (MRK.N) Gardasil, which is designed to ward off a virus that is believed to cause some 70 percent of cervical cancer cases, Oncophage is designed to target the cancer directly and delay or prevent it from spreading once it has developed. (Reporting by Ben Hirschler; Editing by Michael Kahn)