A trial looking at zoledronic acid to try to stop breast cancer coming back (AZURE)

The research team found that overall, adding zoledronic acid to standard treatment for breast cancer doesn’t help stop the cancer coming back. But women who had already been through the menopause did have a small, but important, benefit.

This was a large phase 3 trial. It recruited over 3,300 women from 174 hospitals in 7 countries. Everyone taking part had had (or were due to have) surgery for breast cancer that hadn’t spread to another part of the body.

They were recruited into 1 of 2 groups

• 1,678 were in group 1 (the control group) and had standard treatment
• 1,681 were in group 2 and had standard treatment and zoledronic acid

The women in group 2 had zoledronic acid every 3 to 4 weeks for the first 6 doses, and then every 3 to 6 months up to a total of 5 years.

The research team looked at the results in 2013 to see how many women had cancer that had started to grow again. They found there was no real difference between the 2 groups about 7 years after joining the trial. There was no sign of cancer in about 68 out of every 100 women (68%) in each group.

They also looked at how many women were still alive at this time. Again, there was little difference between the 2 groups, with about 79 out of every 100 women (79%) in each group alive.

When the research team looked at the results in more detail they found that women who had been through the menopause before they were diagnosed with breast cancer did have some benefit from zoledronic acid. Unfortunately, younger women who hadn’t been through (or were still going through) the menopause when they were diagnosed didn’t have the same benefit.

The research team looked at the results of the 1,041 women who had been through the menopause more than 5 years before joining the trial. They found that there was no sign of cancer 7 years after joining the trial in

• 69 out of every 100 women (69%) who had zoledronic acid
• 64 out of every 100 women (64%) who didn’t have zoledronic acid

They also looked at how many women were living 7 years after being joining the trial, and found it was

• 78 out of every 100 women (78%) who had zoledronic acid
• 74 out of every 100 women (74%) who didn’t have zoledronic acid

26 women in the zoledronic acid group had a side effect called osteonecrosis of the jaw. There were another 7 possible but unconfirmed cases. No one in the control group had this side effect.

The trial team looked at the number of bone fractures in each group in 2011.They found there were fewer bone fractures in zoledronic acid group – 65, compared to 110 in the control group.

The research team concluded, on balance, that zoledronic acid is a useful treatment for older women who have been through the menopause before they are diagnosed with breast cancer.

We have based this summary on information from the team who ran the trial. 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. We have not analysed the data ourselves.