LONDON (Agence de Presse Medicale for Reuters Health) - British researchers said on Monday that clinical trials showed that a simple blood test can predict which patients with ovarian cancer will become resistant to chemotherapy.
The finding opens up the possibility that women found to be at high risk could be offered novel therapies in addition to conventional chemotherapy, said Robert Brown, professor of cancer therapeutics at Glasgow University.
He told a Cancer Research UK conference in Harrogate that the test identifies the gene methylation process which can tell if the genes which allow chemotherapy to trigger cancer cell death, will be switched on or off if the tumour recurs.
He said methylation changes in plasma DNA were examined using PCR in a large international phase lll trial comparing paclitaxel-carboplatin versus docetaxel-carboplatin as first line therapy.
Results showed that the proportion of samples positive for methylation increased from 12% (16 of 138) of plasma samples before chemotherapy to 33% (45 of 138) at relapse. And 25% (34 of 138) showed methylation in the relapse sample but not in the pre-chemotherapy sample.
Data from 131 patients was suitable for survival analysis. Of these patients, 78 had died, giving the methylation study 74% power to detect a hazard ratio of 2 for the effect of acquired methylation on survival time from progression.
Brown said the data “opened the possibility of using a relatively non-invasive blood test to stratify and identify those patients who relapse following standard first line chemotherapy who may benefit most from novel epigenetic therapies alone or in combination with conventional chemotherapy.”
He said his group had started phase l clinical trials of the demethylating agent decitabine to see if this drug would switch back on the genes that methylation had switched off.
A predictive test would be particularly useful in ovarian cancer, which recurs in most patients, leading to an overall 5-year survival for patients with advanced disease of less than 30%. However it could also be used for other cancers where drug resistance is a problem, Brown said.
MeSH Headings:Antineoplastic Agents, Combined: Biological Sciences: Biology: Genetics: Pharmacogenetics: Biological SciencesCopyright © 2002 Reuters Limited. All rights reserved. Republication or redistribution of Reuters content, including by framing or similar means, is expressly prohibited without the prior written consent of Reuters. Reuters shall not be liable for any errors or delays in the content, or for any actions taken in reliance thereon. Reuters and the Reuters sphere logo are registered trademarks and trademarks of the Reuters group of companies around the world.
