A newly approved breast cancer drug could be highly effective against some forms of pancreatic cancer, including metastatic cancer. The study also revealed a new straightforward way to test which patients might respond positively to treatment.
Dr Marina Pajic, leader of the Personalised Cancer Therapeutics Group at the Garvan Institute of Medical Research, said the test was designed to meet an urgent need for new, targeted therapies for pancreatic cancer.
“We know that the underlying drivers of pancreatic cancer at the molecular level differ from person to person. Despite this, there are currently few treatments that directly target the molecular drivers of an individual’s pancreatic cancer, but only a one-size-fits-all combination chemotherapy approach – and the fact is that this simply isn’t effective for most patients,” said Dr Pajic.
The researchers examined over 550 tumour biopsies from pancreatic cancer patients. In about two-thirds of those tumours, they found, a cellular pathway known as the ‘Cdk4/6 pathway’ was switched on, driving tumour cells to grow and divide.
“This was an important clue for us and we started to look in depth at how best to block the Cdk4/6 pathway. We know that the drug palbociclib switches off the Cdk4/6 protein, so we reasoned that palbociclib might halt the growth of the many pancreatic cancers where this pathway is on.”
The researchers also showed that the RB protein – another protein in the Cdk4/6 pathway – was present in high levels in Cdk4/6 “ON” tumours and so could act as a biomarker of the tumour subtype.
“Having a good biomarker is essential for personalised medicine, because it gives us a way to predict who is likely to respond to treatment,” said Dr Angela Chou a pathologist and researcher at Garvan and St Vincent’s Hospital, Sydney.
Dr Chou also said that RB levels help to identify and treat metastatic tumours.
“Excitingly, data from our patient samples shows us that, if a primary tumour has high RB levels, then it’s likely that the metastatic tumours will also. This means there’s a possibility that both primary and metastatic tumours could be targeted in the same patient in the future,” added Dr Chou.
More information on the potential of palbociclib as a targeted therapy to treat pancreatic cancer could be coming soon.
“Therapies that target the Cdk4/6 pathway are already in clinical trials for pancreatic cancer here in Australia – and we’d love to see testing for tumour RB levels in those trials to learn more about its power to predict treatment success in people,” Dr Chou concluded.
Currently, five-year survival rates after pancreatic cancer diagnosis stand at just 7% – a figure that has scarcely improved in the last four decades. Most pancreatic cancers are diagnosed after the tumour has spread beyond the pancreas, making treatment even more challenging.
The findings have been published this week online in the journal Gut.
The research news was originally posted on Garvan’s website.
ACRF has proudly provided Garvan Institute with $6.1m towards cancer research since 2003.