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Overall survival results from ICON6 recurrent ovarian cancer trial

14 June 2017

The ICON6 trial team have released updated results suggesting that adding the drug cediranib to chemotherapy may improve survival for women with recurrent ovarian cancer. These results were presented on Friday 2 June at the American Society for Clinical Oncology (ASCO) conference in Chicago.

This is the first trial to show that an oral medicine of this type can help women with ovarian cancer. Last year the trial team published results showing that adding cediranib to chemotherapy delayed time to the disease getting worse. The data also suggested that women who received cediranib during and after chemotherapy may live longer, but there was not enough data at the time to be sure. We now have more data, so carried out a pre-specified analysis to update the results.

Cediranib is a tablet that stops tumours developing the blood vessels they need to keep growing. It is simple to take, and most women in the trial had only mild or moderate side-effects that were not difficult to manage.

The latest results showed that taking cediranib daily during chemotherapy and afterwards increased how long women lived for by around 5 months, (from 29 months to 34 months) on average. The evidence is not strong enough for us to be sure this survival difference is real. We would have needed a larger trial to be able to confident a difference of this size was definite.

The ICON6 trial looked at 456 women with ovarian cancer that had come back after initial treatment. Patients were divided at random to receive either standard chemotherapy plus a placebo, or standard chemotherapy with cediranib for either the length of chemotherapy, or for 18 months.

We already knew that taking cediranib daily during chemotherapy and afterwards for a total of up to 18 months increased the length of time before the disease got worse by an average of 2.3 months, from 8.7 to 11.0 months. There is enough evidence for us to be confident that the drug definitely does delay the disease getting worse.

The trial was originally planned to be larger, which would have given us power to detect a difference in how long women lived. However, disappointing results in other types of cancer led to an interruption of drug supply and  the trial ended up smaller than had been planned.  On the basis of these encouraging results, the company who make the drug have now resumed manufacture and are supporting additional trials.

The trial was an international collaboration between members of the Gynecologic Cancer Intergroup (GCIG), and recruited women from the UK, Canada, Australia and Spain. It was co-ordinated by the MRC Clinical Trials Unit at UCL.