WA researchers believe they may be close to an important breakthrough in treating the most common childhood brain cancer, medulloblastoma.
Their hopes centre on a new class of drug that has been shown to double – and in some cases even triple – the lifespan of laboratory mice implanted with the highly aggressive childhood brain cancers.
The drugs, which are already used to treat adult cancer patients, have been identified in a study funded by a Telethon-Perth Children’s Hospital Research Fund (TPCHRF) grant and led by Princess Margaret Hospital paediatric oncologist and neuro oncologist Nick Gottardo.
Dr Gottardo said that although it would be several years before they would know for sure whether cell cycle checkpoint kinase inhibitors – otherwise knowns as CHKis could be used routinely on paediatric patients, preliminary results were exciting.
If further research can confirm their expectations CHKis may be used in young cancer patients to enhance the effectiveness of chemotherapies and limit the need for radiotherapy.
Dr Gottardo said chemotherapy made patients very ill and radiotherapy could cause serious long-term side effects, particularly in young children whose brains were still developing.
“But chemotherapy often fails to totally destroy the cancer. This is due to a natural repair mechanism in the cancer cells which enables them to recover and for the cancer to return,” he said.
CHKis work by blocking this repair mechanism.
Dr Gottardo hopes that CHKis, given early in treatment, could minimise the amount of chemotherarpy and radiotherapy needed.
Dr Gottardo said the drugs’ potential to treat medulloblastoma emerged when they were tested on mouse models developed to mimic brain cancers in children. These models – referred to as “mouse avatars” – had cancer cells implanted into the same part of their brain as the paediatric patient from whom they were taken, providing a closer representation of the disease.
“If our results can be replicated elsewhere around the world, we’ll be looking to start clinical trials,” he said.
Testing in the mouse models followed the researchers’ screening of approximately 3500 existing drugs to identify any capable of destroying the brain cancer cells.
In this earlier phase of the study, the researchers cultured brain cancer cells in test tubes and employed high-throughput robotic technology to investigate a wide range of drugs that included everything from new and well established compounds to drugs used to treat cancer in adults as well as epilepsy and anti-malarial medications.
“The benefit of looking at existing drugs is that they can be taken to the clinic quickly because there is already a wealth of data on them, such as dosage and side effects profile,” Dr Gottardo explained.
“By ‘repurposing’ an existing medication we can also avoid the enormous costs associated with bringing a new drug to market.”
Only 1.5 per cent of the drugs investigated in the screening killed the brain cancer cells and advanced through to the mouse-modelling phase.
Dr Gottardo said brain tumours were the most common solid cancer in children, affecting about 200 children in Australia every year.
He said there was a big need to find new drugs that could be used to improve the effectiveness of chemotherapy which was why the prospect of an effective medication that was already readily available was so exciting.
He said any use of CHKis to treat medulloblastoma would be in combination with other drugs.
Dr Gottardo’s research was undertaken at the Telethon Kids Institute.
WA’s Chief Medical Officer Gary Geelhoed said Dr Gottardo’s project was an example of how TRCHRF-funded research had the potential to make a real difference to patient care and outcomes.
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