An experimental pill for leukemia has shown promise in early clinical trials — sending a third of patients with aggressive disease into complete remission.
The drug — revumenib — was also credited with putting half of patients with acute myeloid leukemia (AML) into partial remission during phase one clinical trials.
Dr Scott Armstrong, a blood cancer expert at the Dana-Farber Cancer Institute in Boston, Massachusetts, who is running the trial, heralded the results as ‘very encouraging’. But he said more research was needed to prove that the drug worked.
He said if more rigorous trials are successful his team could apply for Food and Drug Administration (FDA) approval by the end of this year. The initial trial did not include a control group, meaning the drug was not tested against current treatments.
Researchers at the Dana-Farber Cancer Institute in Boston, Massachusetts, said that a third of patients on revumenib went into complete remission (stock image)
Acute myeloid leukemia is a type of blood cancer that affects white blood cells, causing them to start dividing uncontrollably and become abnormal — leaving them unable to fight infections.
There are about 59,000 cases diagnosed every year in the United States and 23,700 people die from the cancer.
It is notoriously hard to treat because the cells involved are diverse and can mutate rapidly, making them difficult to target with novel treatments like immunotherapy.
They also divide quickly and spread to different areas of the body, which leaves doctors struggling to eliminate them without harming healthy tissue.
In the study, published this month in the journal Nature, researchers focused on leukemias that were triggered by mutations in the NPM1 and KMT2A genes.
This accounts for about 40 percent of America’s leukemia cases. Up to 80 percent of people diagnosed with these mutations in their leukemia die within five years.
In leukemia with these mutations, a protein called menin binds to genes that trigger cancerous cells to keep growing and dividing.
To break this cycle, revumenib uses a molecule that binds to menin stopping it attaching to and, therefore, triggering the genes.
In their study, scientists administered the drug to 68 patients who had relapsed leukemia or leukemia that did not respond to treatment. Nearly all had leukemia with NPM1 or KMT2A mutations and they were about 42 years old.
Patients were asked to take the drug, administered in a capsule, twice a day — with each dose 12 hours apart.
They were tracked for about a year on average.
Results showed that a total of 18 patients (30 percent) had complete remission of the cancer during the study, meaning all signs and symptoms of the cancer had disappeared.
The average time to reach complete remission was two months, the scientists said.
Another 32 patients (53 percent) were also shown to have partial remission, or a decrease in the size of tumors or the extent of cancer in the body.
They remained in partial remission for nine months.
Overall, patients survived for about seven months after the start of the study.
Nearly all patients experienced adverse effects, with the most common being an irregular heartbeat and nausea.
Seven people had to withdraw from the study because of a severe reaction to the drug.
There was, however, evidence in some participants that cancerous cells had developed resistance to the drug.
Dr Armstrong, who led the study, said: ‘For patients with acute leukemia who have undergone several previous treatments, this is a very encouraging result.
‘However, after the second cycle of treatment some patients did develop resistance to revumenib.’
Phase one trials are designed to test the safety and optimal dose of an experimental treatment.
Currently those with NPM1-mutated leukemia or the KMT2A mutations are offered chemotherapy to fight the disease.
Surgery is rarely used to treat acute myeloid leukemia. Radiotherapy may be used in some cases where the cancer has spread out of the bone marrow and blood.
About two out of three of these patients will then go into remission, the American Cancer Society says.
Doctors say that those who have NPM1 leukemia tend to have better responses to chemotherapy treatments.
WHAT IS LEUKAEMIA?
Leukaemia is a cancer that starts in blood-forming tissue, usually the bone marrow.
It leads to the over-production of abnormal white blood cells, which fight off infections.
But a higher number of white blood cells means there is ‘less room’ for other cells, including red blood cells – which transport oxygen around the body – and platelets – which cause blood to clot when the skin is cut.
There are many different types of leukaemia, which are defined according to the immune cells they affect and how the disease progresses.
For all types combined, 9,900 people in the UK were diagnosed with leukaemia in 2015, Cancer Research UK statistics reveal.
And in the US, around 60,300 people were told they had the disease last year, according to the National Cancer Institute.
Most cases have no obvious cause, with the cancer not being contagious or inherited.
Leukaemia generally becomes more common with age – the exception being acute lymphoblastic leukemia, which peaks in children.
Other risk factors include being male, exposed to certain chemicals or radiation, and some bone-marrow disorders.
Symptoms are generally vague and get worse over time.
These can include:
- Frequent infections
- Heavy periods, nose bleeds or bleeding gums
- Shortness of breath
Acute leukaemia – which progresses rapidly and aggressively – is often curable via chemo, radiotherapy or a stem cell transplant.
Chronic forms of the disease – which typically progress slowly – tend to incurable, however, these patients can often live with the disease.
Source: Leukaemia Care