A study looking at tamoxifen for people with myeloproliferative disorders (TAMARIN)

Cancer type:

Blood cancers

Myelofibrosis

Polycythaemia

Thrombocythaemia

Status:

Results

Phase:

Phase 2

This study was for people with a type of blood cancer that causes the bone marrow to produce too many blood cells. This includes:

These conditions are also called myeloproliferative neoplasms or myeloproliferative disorders.

The study was open for people to join between 2016 and 2019. The team published the results in 2023.

More about this trial

Most treatments for myeloproliferative disorders (MPDs) aim to control the number of blood cells in the blood. This reduces the risk of blood clots and bleeding and helps with symptoms, such as pain.

Many people with MPDs have changes (mutations Open a glossary item ) to certain genes found in blood cells. These are the JAK2 gene and the CALR gene.

The JAK2 gene makes a protein that controls how many blood cells are made.
The CALR gene makes a protein which can affect other proteins that are made in blood cells. Some of these proteins affect the way the cell grows and divides.

There are already some treatments that reduce the number of cells that have these gene changes. For example, interferon and ruxolitinib.

They have helped people with MPDs. But some people can’t cope with the side effects of these treatments.

Tamoxifen is a drug currently used to treat breast cancer. Laboratory research has shown that tamoxifen reduces the number of abnormal blood cells. And this happened most in the blood cells carrying the JAK2 and the CALR gene changes. But researchers didn’t know if this would happen in people with MPDs.

In this study, people had tamoxifen alongside the usual treatment for their MPD. Doctors wanted to see if adding tamoxifen helps to reduce the number of cells carrying genetic changes.

Summary of results

This trial showed that tamoxifen might help people with MPD who have a change in the JAK2 gene or the CARL gene.

Results
This was a phase 2 trial Open a glossary item . Everyone was to take tamoxifen for 24 weeks. Of the 38 people who took part 32 people completed the treatment.

At 24 weeks of treatment the team looked at the number of cells carrying the gene change. They found that for:

3 people the number of cells had reduced by half (50%) or more
5 people the number of cells had reduced by a quarter (25%) or more

The team looked at the number of people whose MPD symptoms had reduced. They found that for the people with ET or PV:

4 out of 21 people (19%) their symptoms had gone away
15 out of 21 people (71.4%) their symptoms had reduced
2 out of 21 people (9.5%) there were no changes to their symptoms

12 people stopped treatment. One stopped because they developed a blood clot. 11 people stopped because of other side effects.

Side effects
The most common side effects that people had during the trial were:

tiredness (fatigue)
infections
skin problems
feeling sick (nausea)
hot flashes
muscle and joint pain
headache
problems with the digestive system

The researchers also looked at the samples that were taken from the people before they started on the study. The team compared these samples to find out if there was a difference between people for who the treatment worked well and those for which it didn’t.

They found there was a difference between the samples from people who responded well to the treatment, compared to those whose symptoms didn’t change. In the future, this kind of information could be used to predict patients that are more likely to do well on treatment.

Conclusion
The team concluded that tamoxifen can help reduce the number of cells that carry the gene change in people with MPD. Tamoxifen should be looked at further for people with MPD. Any future research should carefully consider the risk that some people could develop a blood clot.

The team are not doing any further studies. But this study still adds to our knowledge and understanding of cancer and how to treat it. And might help researchers to consider tamoxifen in future research.

More detailed information
There is more information about this research in the reference below.

Please note, the information we link to here is not in plain English. It has been written for healthcare professionals and researchers.

Tamoxifen for the treatment of myeloproliferative neoplasms: A Phase II clinical trial an exploratory analysis
Z Fang and others
Nature Communications, 2023. Volume 14, pages 7725.

Where this information comes from
We have based this summary on the information in the article above. This has been reviewed by independent specialists (peer reviewed Open a glossary item ) and published in a medical journal. We have not analysed the data ourselves. As far as we are aware, the link we list above is active and the article is free and available to view.