Drugs maker AstraZeneca has won approval from US regulators for its lung cancer treatment Iressa, aimed at patients who do not respond to standard chemotherapy.

Iressa targets advanced cases of non-small cell lung cancer, the most common form of lung cancer in the US.

Astra Zeneca, the UK's second biggest drug company, said the US Food and Drug Administration had given Iressa limited approval based on data from trials which showed 13.6 per cent of patients saw their tumours shrink at least 50 per cent following the treatment.

Analysts believe AstraZeneca needs new drug launches after being hit by delays in winning approval for its products and competition from cheaper, copy-cat drugs.

The group is continuing trial studies in an effort to win full approval for Iressa, which is only to be used as a last resort, after yesterday's announcement.

Approval comes despite a controversial launch for Iressa in Japan, where the drug was introduced in July. It has been linked to more than 100 deaths, while 616 patients are said to have suffered side effects.

AstraZeneca has stood by the drug despite some patients taking it developing interstitial lung disease (ILD), which can also appear as a side effect of chemotherapy or radiotherapy.

The company said last week that deaths among people taking the drug had levelled out and added that it had not been determined whether they were as a result of Iressa.

London company AstraZeneca is hoping Iressa will make up for declining sales of its ulcer treatment Losec. Sales of Losec in the US, where it is known as Prilosec, fell by 60 per cent during the first three months of the year after it was hit by competition from generic versions.

The company employs 10,000 people in the UK, including at its corporate office in London and sites in Alderley Park and Macclesfield in Cheshire, Charnwood in Leicestershire, Avlon near Bristol and Luton. Worldwide it has 54,000 staff.