The trial team found that irosustat didn’t work as well as they had hoped. Instead they found that megestrol acetate worked better to slow the growth of the cancer. As a result, this trial stopped earlier than planned.
This small
phase 2 trial took place worldwide. 71 women took part. They were put into 1 of 2 treatment groups at
random, and:
- 36 had irosustat tablets
- 35 had megestrol acetate tablets
Everyone had treatment for as long as it was working and the side effects weren’t too bad.
Results
The researchers published the results in February 2017.
The researchers did an early analysis of the results in June 2011. They looked at the number of women living whose cancer hadn’t got worse after 6 months of treatment. They found this was:
- just under 4 out of 10 women (36%) who had irosustat
- just over 5 out of 10 women (54%) who had megestrol acetate
Based on this analysis, they decided to stop the trial early. This was because women taking irosustat did worse compared to women having megestrol acetate.
The researchers looked at how well irosustat worked. They found:
- in 3 women the cancer went away a little bit
- in 17 women the cancer stayed the same
- in 14 women the cancer got worse
- they didn’t have the results for 1 woman
They looked at how well megestrol acetate worked. They found:
- in 2 women the cancer went away completely
- in 10 women the cancer went away a little bit
- in 12 women the cancer stayed the same
- in 8 women the cancer got worse
- they didn’t have the results for 2 women
The researchers also looked at the average length of time before the cancer started to grow again. On average this was:
- 16 weeks in women who had irosustat
- 40 weeks in women who had megestrol acetate
The researchers also looked at:
- how well the cancer responded to treatment
- how long women lived for
But they didn’t find a significant difference in either of these.
Side effects
The side effects of both irosustat and megestrol acetate were mild. The most common side effect for both drugs was dry skin. Although women who had irosustat had more problems with this.
Conclusion
The trial team concluded that irosustat didn’t help women with advanced womb cancer or womb cancer that had come back. But it did confirm that megestrol acetate worked for some women.
This trial has increased what we know about what works and what doesn’t for advanced womb cancer.
We have based this summary on information from the research team. The information they sent us has been reviewed by independent specialists (
peer reviewed 
) and published in a medical journal. The figures we quote above were provided by the trial team who did the research. We have not analysed the data ourselves.