Breakthrough treatments are emerging against the commonest form of leukaemia, it was claimed this week at the European Association of Hematology meeting in Amsterdam.
A session hosted by the biopharmaceutical firm Cephalon heard that approval had been given for a Phase III trial of the firm’s SEP-701 treatment for acute myeloid leukaemia (AML).
Alan Burnett, the professor of haematology at the University of Cardiff, said the trial, which is backed by the UK’s Medical Research Council, will test whether SEP-701 boosts survival in AML patients when added to standard chemotherapy.
The drug is a tyrosine kinase inhibitor (TKI), which targets a mutant protein associated with cancerous cells. By neutralising the protein, laboratory tests suggest the drug, which is also known as a FLT3 inhibitor, can prohibit the rapid proliferation of cancer cells.
Prof Burnett said: “I’m fairly optimistic about these drugs. There is some preliminary data emerging from the US that suggests adding FLT3 inhibitors to chemotherapy improves outcome.
“But to really know how effective they are we need large randomised trials and that’s what we’re doing in the UK, and it’s one of the things we’re good at.”
The status of this class of drug has recently been boosted by the impressive long-term clinical outcome data for the TKI drug Glivec (imatinib), sold by Novartis, in the treatment of another blood cancer, chronic myeloid leukaemia.
Experts note, however, that using such treatments against acute myeloid leukaemia is likely to prove more complicated.
“Unfortunately, the AML is a fairly heterogeneous disease. This means there are different types of AML each with their own molecular abnormalities that need to be targeted. That means the emergence of a single blockbuster drug to treat all cases is unlikely,” Prof Burnett said.
Nonetheless, he said that a subset of 25% to 30% of AML patients were likely to benefit from the Cephalon drug, which is one of several new TKIs currently under development for the treatment of this leukaemia. He stressed that for maximum benefits they would probable need to be taken with chemotherapy.
Professor Sergio Amadori, the professor of Haematology at La Sapienza University in Rome, agreed that the new treatments were unlikely to be sufficiently active to be given alone. “We therefore need to understand how to combine them most effectively to existing anthracycline and other chemotherapies,” he said.
AML strikes approximately six adults per 100,000 of the population every year. Ten-year survival rates in patients under the age of 60, who are better able to tolerate aggressive chemotherapy, have risen to 50 per cent.
However, Prof Burnett noted that the majority of victims were over 60 – and that half of these older patients died within three months of diagnosis. “That’s why we desperately need better treatments,” he said.
“People often forget this is largely a disease of older age, and with demographic changes that are happening, the problem is going to increase.”
He hoped that one step forward would the testing of FLT3 inhibitors in older patients.
“I think that this will start to happen the next two to three years,” he said.