Three out of 10 leukaemia patients with certain aggressive forms of the disease that had proved resistant to multiple treatments achieved remission thanks to a new drug, a clinical trial has found.
While only applicable to particular types of leukaemia, the findings with the drug revumenib offer hope that emerging treatments will continue to improve survival rates.
The findings come from a clinical trial in the US, the results of which have been published in leading scientific journal Nature.
In the trial, 20 out of 60 patients with acute leukaemia designated as mNPM1 (caused by mutations of the NPM1 gene) or KMT2Ar (associated with rearrangements of the KMT2Ar gene) experienced remission.
This took an average of just over nine months.
The patients had undergone an average of four previous treatments and nearly half had received at least one stem cell transplant. But these had failed to eliminate the disease.
Revumenib is called a menin inhibitor because of the way it interacts with a protein called menin — the gene for which is mutated in leukaemia patients — and inhibits its disease-causing actions.
Michael Metzger, chief executive of Syndax, the drug company behind revumenib, said the company was “excited” to have the results published “in such a prominent peer-reviewed journal”.
“As we continue to deepen our understanding of the tumour biology driven by the menin-KMT2A interaction, we gain more evidence to support the potential of revumenib as a best-in-class treatment for both mNPM1 and KMT2Ar acute leukaemias,” he said.
He said that by the end of this year, there could be a New Drug Application filing, the process by which companies apply for approval from the US Food and Drug Administration.
This could, Mr Metzger said, result in revumenib becoming the first menin inhibitor approved for use by patients.
A number of other pharmaceutical companies are also developing menin inhibitors, and the latest findings indicate that this could prove to be a successful approach for some patients.
KMT2Ar acute leukaemias account for about 10 per cent of acute leukaemias — types that progress quickly and aggressively — and typically have a poor prognosis, with just a quarter of adults living more than five years.
With mNPM1 leukaemias, which make up around 30 per cent of acute leukaemias, adult survival rates beyond five years are around 50 per cent.
Leukaemia involves the production of large numbers of abnormal forms that do not protect the body from infection as white blood cells, being part of the immune system, normally do.
These abnormal white blood cells additionally hamper the bone marrow’s production of red blood cells and platelets, which are fragments of cells involved in clotting.
Dr Ghayas Issa, assistant professor in the cancer medicine division at the University of Texas MD Anderson Cancer Centre said that the results showed that revumenib “was associated with encouraging clinical benefit”.
These, he said, included “deep molecular remissions and durable responses”, with minimal toxic effects for the patients. In fact, no patients had to discontinue treatment because of side effects.
“Future and ongoing trials may indicate whether treating patients in earlier settings and in combination would provide higher response rates in mNPM1 or KMT2Ar acute leukaemia patients who are less likely to have developed functional mutations,” he said.
While the new clinical trial results are seen as promising, they involve relatively small numbers of patients and much larger-scale trials will be needed before revumenib could be rolled out widely.
These larger trials are now being undertaken and will involve an international group of patients.
Often drug treatments for leukaemia are combined with traditional therapies, such as chemotherapy, to improve survival rates.
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