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People with a severe type of leukaemia could benefit from a milder chemotherapy drug, according to a new US study.
Patients with acute myeloid leukaemia (AML) whose cancer cells carry a particular gene fault generally have a poorer outlook following standard treatment compared to other patients.
But scientists from Washington University School of Medicine in the US found that this group of patients could have improved survival if given a different, less intensive chemotherapy drug – called decitabine.
Although none of the patients were cured with decitabine, said senior study author Professor Timothy Ley, those who responded “live longer than what you would expect with aggressive chemotherapy”.
AML is a type of blood cancer that develops quickly, causing the bone marrow to become crowded with abnormal cells.
Patients are usually given two different chemotherapy drugs in an attempt to kill the leukaemia cells and put the cancer into remission, which is where no more cancer cells can be found in the blood and bone marrow.
While the drugs can cause serious side effects, this is a critical first step in the long-term treatment of the disease, which can include a follow-up bone-marrow transplant.
Some patients don’t respond to the chemotherapy though, particularly those with mistakes in a gene called p53. Remission rates in these patients are low and they typically have a very poor outlook.
In the latest study, published in The New England Journal of Medicine, the researchers found that patients whose cells carried a faulty p53 gene responded very well to decitabine. All 21 patients within this group went into remission.
The team found that survival figures for these patients almost matched those without the gene fault, living for around 12.7 months rather than the typical 4 to 6.
The researchers believe this treatment could open up the opportunity of a stem cell transplant for some patients who previously would not have been eligible for the procedure.
Professor Nigel Russell, a Cancer Research UK-funded scientist from the University of Nottingham, described the results as “promising” and said they should be followed up in larger studies.
“Some patients with AML can be treated with chemotherapy, but those with faults in the p53 gene don’t respond to this standard treatment,” he added.
“In this latest study, researchers found these patients respond well to a drug called decitabine and may survive longer than with standard chemotherapy, but it’s too early to know if the drug can cure them.
“One of our clinical trials, funded by Cancer Research UK, is going to test whether decitabine combined with another drug as a treatment in AML patients with faulty p53, to see if adding this drug can help improve survival.”
Welch, J. S. et al. (2016). TP53 and decitabine in acute myeloid leukemia and myelodysplastic syndromes. NEJM. 375: 21. DOI: 10.1056/NEJMoa1605949