A NEWLY-approved breast cancer drug could be highly effective against some forms of pancreatic cancer, including metastatic cancer.
Researchers from the Personalised Cancer Therapeutics Group at the Garvan Institute of Medical Research also found a straightforward way to test which pancreatic cancer patients might respond positively to treatment, marking a significant step towards personalised medicine for the disease.
Pancreatic cancer is a killer. Currently, five-year survival rates after diagnosis stand at just 7 per cent - a figure that has scarcely improved in the past 40 years.
Most pancreatic cancers are diagnosed after the tumour has spread beyond the pancreas, making treatment even more challenging.
The researchers first examined more than 550 tumour biopsies from pancreatic cancer patients, and in about two-thirds they found a cellular pathway (known as the Cdk4/6 pathway) was switched on, driving tumour cells to grow and divide.
"We started to look in depth at how best to block the pathway," said Dr Marina Pajic, who led the study.
"We know that the (breast cancer) drug palbociclib switches off the Cdk4/6 protein, so we reasoned that palbociclib might half the growth of the many pancreatic cancers where this pathway is 'on'."
The researchers tested the efficacy of the breakthrough breast cancer drug in mouse models of pancreatic cancer. At each step they compared the drug with standard chemotherapy-only approaches.
"Time and again we found that pancreatic tumours with high RV levels (a protein) responded powerfully to palbociclib," said Dr Angela Chou, a pathologist and researcher who is first author on the new study.
"Mice treated with palbociclib as a first-line treatment had a lifespan of more than 100 days longer than those treated with chemo alone - and the effect was even stronger when we combined palbociclib with chemotherapy.
"We also went on to test palbociclib as a second-line treatment following progression of pancreatic cancer and in a model of metastatic cancer - and again, palbociclib extended lifespan far beyond chemotherapy."
The researchers found that as well as targeting tumour cells directly, the drug "remodels" the extracellular matrix - the "web" of molecules that surrounds and organises cells - in tumours with high RB levels.
The research was published online in the journal Gut.
