AstraZeneca’s oncology drug Iressa (gefitinib) could be a new treatment option for women with breast cancer, given alongside aromatase inhibitors and before surgery, according to a Phase II study.

The 56-patient Phase II trial, reported in the journal Lancet Oncology (May issue), found that the combination of Iressa and AstraZeneca’s aromatase inhibitor Arimidex (anastrozole) achieved a reduction in tumour size in 55% of patients, while Iressa plus placebo managed this in 50% of recipients.

AstraZeneca pulled Iressa from the US market late last year after no survival benefit was seen amongst lung cancer patients taking the drug in a major clinical trial [[20/12/04b]]. The firm also withdrew the product’s European filing [[05/01/05a]]. It is still being sold in some markets, albeit with no promotional effort by AstraZeneca, but is a far cry from its once-touted position as one of the firm’s key pipeline prospects.

Iressa sales declined 15% in the first quarter of 2005 to $81 million, dragged lower particularly by a hefty 41% slump in the USA. AstraZeneca is turning its attention to breast cancer in an attempt to revive the fortunes of the drug, and it is conducting a trial - Study 223 – in the same patient population as the Lancet Oncology study.

The primary endpoint of study 223 is to observe changes in a growth-proliferation marker Ki67, a proliferation-related antigen that has been previously validated as a measure of tumour-cell proliferation, said a spokeswoman for the company. Results are scheduled to be available next year.