UK cost agency approves use of Zeltia cancer drug

* Zeltia's Yondelis recommended for soft tissue sarcoma

* Move follows cost pledge to UK by Spanish company

LONDON, Dec 21 (Reuters) - Zeltia's (ZEL.MC) drug Yondelis will be offered as a treatment option for advanced soft tissue sarcoma on Britain's state-run health service, the country's cost-effectiveness watchdog said on Monday.

The National Institute for Health and Clinical Excellence (NICE) said the positive recommendation in its final draft guidance followed a promise by the company to meet the costs of the drug if it is needed beyond the fifth cycle of treatment.

Yondelis was also licensed in Europe last month for ovarian cancer, but it has yet to be considered by NICE for this second use. Yondelis is a key product for the loss-making Spanish company, which forecasts that sales of the drug could reach 300 million euros ($432 million) a year in Europe.

Soft tissue sarcomas are tumours that develop in the soft, supporting tissue in the body, such as fat, muscle and blood vessels. The condition affects around 2,000 people a year in Britain. (Reporting by Ben Hirschler, editing by Will Waterman)