Chronic myeloid leukaemia (CML) research
This page is about research into the causes, prevention and treatments of chronic myeloid leukaemia. You can find information about
Chronic myeloid leukaemia (CML) research
All treatments must be fully researched before they can be adopted as standard treatment for everyone. This is so that we can be sure they work better than the treatments we already use. And so we know that they are safe.
First of all, treatments are developed and tested in laboratories. Only after we know that they are likely to be safe are they tested in people, in clinical trials.
There is a lot of chronic myeloid leukaemia research going on to try and develop new treatments and improve the results of current treatments. Researchers and doctors are looking into biological therapies, high dose treatment with bone marrow transplants and stem cell transplants, and finding leukaemia cells left behind after treatment.
You can view and print the quick guides for all the pages in the Treating CML section.
All potential new treatments have to be fully researched before they can be adopted as standard treatment for everyone. This is so that
- We can be sure they work
- We can be sure they work better than the treatments that are available at the moment
- We know they are safe
First of all, treatments are developed and tested in laboratories. For ethical and safety reasons, experimental treatments must be tested in the laboratory before they can be tried in patients. If a treatment described here is said to be at the laboratory stage of research, it is not ready for patients and is not available either within or outside the NHS.
If you are interested in taking part in a trial, visit our searchable database of clinical trials. Choose 'leukaemia: chronic' from the dropdown menu. If there is a trial you are interested in that is currently recruiting, print off the trial and take it to your own specialist. If the trial is suitable for you, your doctor can refer you to the research team. Leukaemia is a big area of cancer research and most major treatment centres are continually involved in clinical trials.
Most cancers, including leukaemia, will vary from person to person in how quickly or slowly they grow. Researchers have identified some factors that can help to tell doctors how the disease is likely to develop. Doctors can use this type of information to help them decide on the most suitable treatment for you. They call these factors prognostic factors because they influence the likely course of your leukaemia and its treatment.
Several systems have been developed over the years for trying to work out how CML will develop. One system that doctors use is called the Sokal Index. It is named after the doctor who created it. It looks at
- Your platelet count
- The number of leukaemia cells in your blood
- Your age
- The size of your spleen.
The Sokal Index can help doctors to decide who should have more intensive treatment at an earlier stage.
There are different types of biological therapy. Some are described as cancer growth blockers. Cancer growth blockers called tyrosine kinase inhibitors are the main type of treatment for most people with CML. A newer type being tried for CML is vaccine research.
You can find out more about biological therapy trials for CML on our clinical trials database. Go to the advanced search and choose 'Leukaemia, Chronic leukaemia' from the dropdown menu of cancer types and 'Biological therapy' from the list of treatment types. If you want to see all the trials, tick the boxes for closed trials and trial results.
Here you can read about the following treatments
The cancer growth blocker imatinib (Glivec) is the most commonly used treatment for CML. It can control CML for some years for some people. But doctors and researchers are continuing to try to improve the results of this treatment. They are looking at whether it works even better when combined with other treatments.The SPIRIT trial is comparing different doses of imatinib and also combining imatinib with the drug interferon for people with newly diagnosed CML.
The CHOICES trial is combining a drug called hydroxychloroquine with imatinib. The trial is for people with chronic myeloid leukaemia that has responded well to imatinib but has not gone completely. There are still a small number of leukaemia cells left (called minimal residual disease). Everybody taking part in the trial continues to take imatinib but some people will also start taking hydroxychloroquine.
Nilotinib (Tasigna) is another type of cancer growth blocker. It has been approved by the National Institute for Health and Care Excellence (NICE) as a treatment for CML. NICE recommends it when imatinib is no longer working or the side effects of imatinib are severe. One trial is looking at nilotinib for newly diagnosed chronic myeloid leukaemia. It is for people who are Philadelphia chromosome positive, or have a high level of a protein called BCR-ABL (or both), and whose CML is in chronic phase. The researchers are trying to find out whether CML in chronic phase responds better to nilotinib as a first treatment than it does to imatinib.
The CA180226 trial is looking at dasatinib to treat children and young people (20 or younger) who have Philadelphia chromosome positive leukaemia that is not responding to imatinib (Glivec). The researchers want to find out how well dasatinib works for this type of leukaemia in children and young people. They also want to learn more about the side effects in this age group.
Another biological therapy being investigated is called ponatinib (Iclusig). It is a new type of cancer growth blocker that affects cells with a gene change (mutation) called T315I. This gene change is found in some CML cells. This genetic change makes the leukaemia very resistant to treatment. Other drugs available do not work so well in people with this mutation. Ponatinib blocks the growth of cells that have this mutation. In early lab tests it appeared to prevent T315I or other mutations forming.
The PACE trial is looking at ponatinib for Philadelphia positive CML. It is for people who have accelerated phase CML with the T315I mutation. This research is a phase 2 study in people whose CML has become resistant to dasatinib and nilotinib.
The phase 3 trial called EPIC is looking at ponatinib for newly diagnosed CML that is Philadelphia chromosome positive. The people taking part have stable disease which is developing slowly (chronic phase).
A new drug called bosutinib (Bosulif) has been approved in Europe. It is for adult patients with Philadelphia chromosome positive chronic myeloid leukaemia who have already had biological therapy treatment. Research is looking at how well this treatment works compared to other biological therapy drugs.
Most people with CML have leukaemia cells that carry the Philadelphia chromosome. This chromosome has an abnormal gene that tells the cell to make a protein called bcr/abl. CML cells have this protein on their surface. Our immune system should recognise the protein and then know that these cells are not normal. But usually, this immune reaction is very weak in CML, if it happens at all. Doctors are trying ways of helping the immune system to find these abnormal cells. They are making copies of parts of the protein and using them to vaccinate people with CML. They hope that the vaccinations will kick start the immune system so that it destroys the CML cells.
The WIN study is looking at a possible vaccine treatment for people with acute myeloid leukaemia (AML), and chronic myeloid leukaemia. The vaccine is for people whose CML cells have a form of a gene called Human Leucocyte Antigen A2 (HLA A2). The researchers hope the vaccine injection will help boost the immune system to recognise and kill the leukaemia cells.
People with leukaemia often have platelet transfusions during their treatment. These are to prevent bleeding. Chemotherapy can slow down the production of platelets by the bone marrow, so you have fewer platelets circulating in your blood. If your platelet level gets very low, you can bruise easily, have nosebleeds or bleed more than usual from cuts or grazes. Doctors check your level of platelets regularly while you are having chemotherapy. If they are very low, you normally have platelet transfusions through a drip.
Doctors do not yet know if people need these platelet transfusions to prevent bleeding. There are small risks linked to having platelet transfusions. Some people have a reaction to the platelets and sometimes this can be serious. Also, there is a small risk of getting an infection.
There is a UK trial finding out if patients need preventative platelet transfusions when there are no signs of bleeding. It wants to see whether it is safe to wait until you have early signs of bleeding, such as bleeding gums, before having a platelet transfusion. The aim is to compare different ways of using platelet transfusions. This may affect the way doctors use them in the future.
You can find out about trials for CML on our clinical trials database. Click on 'chronic leukaemia' in the dropdown menu of cancer types.
Researchers are looking at a new chemotherapy drug called omacetaxine for chronic myeloid leukaemia. Omacetaxine is also called Synribo. You have it as an injection under the skin.
There is a trial using omacetaxine for CML in people who have had other treatments. People in the trial had already had treatment with 2 different biological therapy treatments, such as imatinib or nilotinib. But their leukaemia had not responded to the treatment or had become resistant to these drugs. This trial wants to find out whether omacetaxine works as a treatment in this situation. It has now closed and we are waiting for the results.
High dose chemotherapy followed by donor bone marrow or stem cells (transplant) can cure some people with CML. But this is very intensive treatment and some people do not survive the complications. Because biological therapy can work very well in controlling CML, doctors think very carefully about who they should offer high dose treatment to. We know from research that people most likely to do well after a transplant are
- CML patients under 45 years old with a brother or sister who is a full match
- Or people under 35 with a fully matched donor who is not a relative
The UK Haplo study is looking at using donor stem cells from a family member who is at least a 50% match with the person having the stem cell transplant. As above, in most allogeneic transplants, the donor is someone who is a very close match to the person having the transplant. This is usually a brother or sister. It could also be from a donor who isn't a relative. But doctors can't find a match for about a third of those needing a transplant. An option for these people is a half matched transplant, where the donor is at least 50% match with the person having the transplant. In the past these transplants have been difficult to do. You can react to the donor cells, causing a severe immune response. But researchers think they have found a way to deal with this by using a drug called cyclophosphamide.
The aims of the UK Haplo study are to find out how well high dose cyclophosphamide works with a half matched stem cell transplant, how safe it is, and to learn more about the side effects and quality of life for people having this type of transplant.
Doctors are looking at improving how they do bone marrow and stem cell transplants for chronic leukaemia. They would like to lessen the side effects if possible, because they can be severe and even life threatening.
A new procedure called mini transplant is being investigated for people with leukaemia. Some doctors call this RIC transplant, which stands for reduced intensity conditioning.
With a mini transplant, the chemotherapy doses are not as high as with a regular transplant, so the side effects are not as severe. After the chemotherapy, you have bone marrow or stem cells from someone else (a donor). The chemotherapy treatment you've had suppresses your immune system and allows the donor's blood stem cells to start producing blood cells. The donor cells see your CML cells as foreign (because they are yours and not the donor's) so they kill them.
Because the chemotherapy doses are lower, there may still be some remaining leukaemia cells after a mini transplant. If this happens, you need to have more white blood cells from your donor. You have these through a drip into a vein. Doctors call this donor lymphocyte infusion or DLI. The donor cells attack any remaining leukaemia cells.
A small trial looked at having a mini transplant followed by imatinib for a year, to see if it reduced the chance of the CML coming back. The researchers found that adding imatinib increased the amount of time before the CML came back. And there was a low risk of side effects with this combination of treatment.
The RIC UCBT trial is looking at using stem cells collected from the umbilical cords of newborn babies. The cells are given to people after a mini transplant. These cord blood transplants are for people who don't have a relative who can be their stem cell donor. Doctors hope that the umbilical cord stem cells will cause fewer side effects than adult stem cells.
One problem with treating leukaemia is that even if you seem to have been successfully treated, there can be very small numbers of leukaemia cells left behind. The numbers are so small that the usual blood and bone marrow tests cannot pick them up. You may hear your doctor call this minimal residual disease (MRD).
Scientists are exploring new ways of finding out if there are leukaemia cells left behind after the disease appears to have clinically gone (remission).
One way of doing this is with a test called the polymerase chain reaction (PCR). This test can find one leukaemia cell among a million normal cells. It can help doctors to find out how well your chemotherapy has worked in killing off your leukaemia cells. This test can help to tell the doctor whether your leukaemia is likely to come back (relapse).
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