A trial looking at zoledronic acid for breast cancer that has spread to the bones (BISMARK)

Cancer type:

Breast cancer




Phase 3

This trial compared different ways of giving zoledronic acid for breast cancer that has spread to the bones. This trial was supported by Cancer Research UK.

When cancer spreads to the bone it can make the bone weaker and cause pain. Drugs called bisphosphonates can slow down the damage and reduce pain. Zoledronic acid (Zometa or zoledronate) is a bisphosphonate.

Doctors often prescribe zoledronic acid through a drip into a vein, once every 3 to 4 weeks. This is the standard treatment (S-ZOL) used in this trial. But they wanted to find out if it’s better to use a urine test to decide how often to give zoledronic acid. The test measures the level of a marker Open a glossary item called NTX, which indicates the rate of bone damage. This treatment is called bone marker directed treatment (M-ZOL).

This trial compared S-ZOL and M-ZOL. The aim was to find out if using bone marker directed treatment worked as well as standard treatment for reducing bone pain and weakness.

Summary of results

The research team found that using bone marker directed treatment wasn’t better than the using standard treatment.

This trial recruited slower than hoped, and closed earlier than expected having recruited just 289 people with advanced breast cancer. Of these

  • 146 had standard zoledronic acid treatment (S-ZOL) once every 3 to 4 weeks
  • 143 had marker directed zoledronic acid treatment (M-ZOL)

How often people in the M-ZOL group had treatment depended on the level of NTX marker in their urine. It ranged from every 3 or 4 weeks, to every 15 or 16 weeks.

The research team looked at how many people developed problems with their bones that required medical attention. These are called skeletal related events (SRE) and include

They found that just over 3 out of 10 people (32%) who had standard treatment had at least one SRE, compared to nearly 4 out of 10 (38%) who had marker directed treatment. These results are similar, but they found that more people who’d had marker directed treatment had 2 or more SREs.

It is difficult to draw firm conclusions from this trial because it didn’t recruit as many patients as hoped. But the research team conclude that using markers to decide how often to give zoledronic acid is not as good as standard treatment every 3 to 4 weeks.

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 Open a glossary item) but may not have been published in a medical journal.  The figures we quote above were provided by the trial team. We have not analysed the data ourselves.

Recruitment start:

Recruitment end:

How to join a clinical trial

Please note: In order to join a trial you will need to discuss it with your doctor, unless otherwise specified.

Please note - unless we state otherwise in the summary, you need to talk to your doctor about joining a trial.

Chief Investigator

Professor Robert Coleman

Supported by

Cancer Research UK
Experimental Cancer Medicine Centre (ECMC)
National Institute for Health Research Cancer Research Network (NCRN)
University of Leeds
University of Sheffield

Other information

This is Cancer Research UK trial number CRUK/05/18.

Freephone 0808 800 4040

Last review date

CRUK internal database number:

Oracle 852

Please note - unless we state otherwise in the summary, you need to talk to your doctor about joining a trial.

Caroline took part in a clinical trial for breast cancer

“I had treatment last year and I want to give something back.”

Last reviewed:

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