Experimental pill breakthrough sees cancer vanish in a third of leukaemia patients

Terminal leukaemia patients who were not responding to treatment now have hope for a cure, thanks to a new experimental pill called revumenib.

This drug has completely eliminated cancer in a third of the participants in a long-awaited clinical trial in the United States.

Although not all patients showed complete remission, scientists remain hopeful as the results indicate that the pill might pave the way to a cure for leukaemia in the future.

"We're incredibly hopeful by these results of patients that received this drug. This was their last chance," said study co-author Dr Ghayas Issa, a leukaemia physician at the MD Anderson Cancer Center at the University of Texas.

"They have progressed on multiple lines of therapy and a fraction of them, about half, had disappearance of their leukaemia cells from their bone marrow," he told Euronews Next.

How does this pill work?

Acute myeloid leukaemia (AML) is a type of cancer that attacks the bone marrow, where blood cells are produced, and causes the uncontrolled production of defective cells.

Revumenib is a new class of targeted therapy for acute leukaemia that inhibits a specific protein called menin. The drug works by reprogramming leukaemia cells back into normal cells.

Menin is involved in the complex machinery that gets hijacked by leukaemia cells and causes normal blood cells to turn into cancerous ones.

By using revumenib, Issa explained, the engine is turned off and leukaemia cells are turned back into normal cells, resulting in remission.

This formula has already saved 18 lives as part of the clinical trial, whose promising results were published this month in Nature.

The preliminary results showed that 53 per cent of patients responded to revumenib, and 30 per cent had a complete remission with no cancer detectable in their blood.

Based on the data from this trial, in December 2022 the US Food and Drug Administration granted revumenib "breakthrough therapy designation" to help fast-track its development and regulatory review.

A leukaemia cure, but not for everyone

"This is definitely a breakthrough and it's a result of years of science. A lot of groups had worked hard in the lab to understand what is causing these leukaemias," Issa said.

However, he explained that the drug does not work for all patients. It is for a specific subset of leukaemias that generally have missing or mislabeled genes or a chromosome fusion.

The experimental pill targets the most common mutation in acute myeloid leukaemia, a gene called NPM1, and a less common fusion called KMT2A. Combined, these mutations are estimated to occur in about 30 to 40 per cent of people with acute myeloid leukaemia.

The phase 1 trial enrolled 68 patients at nine US hospitals. All of them had seen their leukaemia return after other treatments or had never responded well to traditional chemotherapy drugs in the first place.

Among them was Algimante Daugeliate, a 23-year-old Lithuanian architect diagnosed with leukaemia. She had received two bone marrow transplants from her sister, but all other treatments had failed. Her doctors had even considered palliative care to ease her suffering.

"I was desperate. It was like living through a horrible movie. I felt like death was imminent, and I was just 21 years old," she told El Pais.

However, once she started taking revumenib two years ago, Daugeliate made a full recovery. Since then, she has been able to resume her normal life, graduating from college and working at an architecture studio in Copenhagen.

Strong impact for limited side effects

According to Issa, although this drug is fairly safe when compared to standard treatments for leukaemia, two main side effects have been identified.

The first affects the heart’s electrical system and can be detected with an electrocardiogram (ECG). However, reducing the dosage or halting the treatment resolved the issue in all cases, Issa said.

The second side effect is referred to as differentiation syndrome - a group of potentially life-threatening reactions to blood cancer treatments - but it can be managed effectively if it’s recognised early and appropriate measures are taken to shut it down. According to Issa, all cases of differentiation syndrome in this study were successfully managed without any complications for the patients.

The study is still in its early stages and the results remain preliminary. Phase I studies like this one aim to test whether a drug is safe and to find the highest dose that can be given to them without causing severe side effects.

A phase II study specifically looking at the effectiveness of revumenib is now underway.

Twelve patients in the trial who responded to the drug went on to receive a stem cell or bone marrow transplant. Such transplants require that patients have no cancer or only very low levels of cancer in their blood - and revumenib helped them get there.

While the experimental pill is not a definitive cure, the researchers who worked on the trial are optimistic.

"In the future, we plan to combine this pill with standard treatments that we have currently for acute leukaemias," said Issa.

"That is the most likely strategy to get us to cures where patients don't have to see leukaemia doctors after that and don't need treatments for leukaemia".