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By Ben Hirschler
MADRID, Sept 28 (Reuters) - Continuing to give AstraZeneca's drug Iressa plus chemotherapy to lung cancer patentswhose disease has worsened after previously taking the medicineon its own does not provide any benefit.
Some doctors had hoped that extending the use of Iressa incombination with chemotherapy would help to keep cancers at bay,even when tumour cells had started to develop resistance to thedrug.
But a clinical study presented at the European Society forMedical Oncology annual congress on Sunday found nostatistically significant improvement in the length of timepatients lived without their disease getting worse.
The Phase III study, involving 265 patients, tested Iressaplus chemotherapy to chemotherapy alone. It was sponsored byAstraZeneca.
Lead researcher Tony Mok of the Chinese University in HongKong said the result suggested doctors should not prescribeso-called EGFR tyrosine kinase inhibitor drugs like Iressa whenpatients' disease had progressed after first-line use of thedrugs.
Data on whether patients had a better overall chance ofsurvival in either arm of the study was inconclusive, Mok said,although there was a suggestion of improved survival in thosewho did not take Iressa. "This needs to be monitored veryclosely in future," he said.
Drugs like Iressa and Roche's rival lung cancerpill Tarceva have been on the market for several years andprovide a valuable treatment option for some lung cancerpatients with a certain genetic mutation.
That mutation affects around 10 to 15 percent of Europeanand American patients with non-small cell lung cancer and 30 to40 percent of those in Asia.
A new generation of targeted lung cancer drugs are now beingdeveloped to target a genetic mutation that helps tumours evadecurrent treatments like Iressa and initial test results havebeen promising.
One of the new drugs is AstraZeneca's experimental productAZD9291. AstraZeneca believes its new-generation medicine couldsell as much as $3 billion a year - considerably more thanIressa's sales of $647 million last year. (Editing by Susan Thomas)
