Retrospective study backs Iressa use in oesophageal cancer
pharmafile | November 5, 2014 | News story | Research and Development, Sales and Marketing |Â Â AstraZeneca, Cancer, Cancer Oesophagus Gefitinib, Iressa, gefitinib, oncologyÂ
A group of oesophageal cancer patients can increase their survival by six months or more if treated with AstraZeneca’s Iressa, according to a new study.
The Cancer Oesophagus Gefitinib (COG) trial failed to show any benefit for Iressa (gefitinib) when its results were first published, but a follow-up study called TRANS-COG – which employed molecular analysis of tumour samples – found the drug was significantly more effective in a subgroup of patients.
Specifically, patients with two copies of the EGFR gene – around one in six of the total study population – derived the most benefit from the drug, with some achieving disease control for almost two years.
That is an extraordinary result, as Iressa is the first treatment ever to show improved survival in patients with advanced oesophageal cancer whose initial course of chemotherapy treatment has failed, according to Russell Petty of the University of Aberdeen, who presented the results at the National Cancer Research Institute (NCRI) Cancer conference this week.
It is also the first time a targeted treatment of any kind has proved effective in this disease, although chemotherapy and some targeted drugs have shown benefit in the second line treatment of other cancers of the gastrointestinal system, including stomach cancer.
TRANS-COG looked at tumour samples from 295 deceased oesophageal cancer patients who had received either gefitinib or placebo as part of the COG trial, and found 48 had extra EGFR copies in their tumour cells.
All told, 13% of those who had gefitinib survived for at least a year, according to Petty, while none of the patients who received a placebo survived that long.
“To date there’s been disappointingly little progress in treating this cancer type, which kills nearly 8,000 people a year and sadly is often diagnosed late making it difficult to treat successfully,” says Petty.
“It is thought that up to 16% of oesophageal cancer patients could benefit from gefitinib, providing valuable extra months of life to people who would otherwise have had very few options available to them,” he adds.
Iressa was approved more than a decade ago to treat advanced EGFR mutation-positive non-small cell lung cancer (NSCLC), and made sales of $316m in the first six months of this year, a small decline thanks to increased competition in the NSCLC category.
While AZ has not indicated it will make a formal marketing application for Iressa as an oesophageal cancer treatment, the drug could still be prescribed off-label for oesophageal cancer patients with the double EGFR mutation.
Screening of patients for eligibility for treatment could soon be much easier, following a positive opinion from the Committee for Medicinal Products for Human Use (CHMP) for a blood test for EGFR status – that will provide a simpler alternative to the current biopsy method.
“Although the survival benefit for these patients was relatively modest, this trial is an important step forwards for a type of cancer where progress in treatment has fallen behind other cancers in recent decade,” comments Professor Matt Seymour, NCRI’s clinical research director.
Phil Taylor
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