Researchers have shown in preclinical models breast cancer drug Palbociclib effectively targets a major subtype of pancreatic cancer.

A new "breakthrough" drug approved to treat breast cancer could be used as a powerful weapon against aggressive forms of pancreatic cancer.

Australia's Garvan Institute of Medical Research has shown in preclinical models that palbociclib effectively targets a major subtype of pancreatic cancer that affects two-thirds of all patients with the deadly disease.

Patient trials are underway and lead research author Dr Marina Pajic says it's hoped the drug can be easily repurposed.

"We are thrilled to have shown in preclinical models that the breakthrough breast cancer drug palbociclib targets a major subtype of pancreatic cancer," she said.

The five-year survival rate of pancreatic cancer is seven per cent, with standard therapy a "one-size-fits-all" combination chemotherapy approach.

Dr Pajic says the study was designed to meet an urgent need for new, targeted therapies.

"We know 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."

Hoping to benefit from all the advances made in the fight against breast cancer, Dr Pajic and her team turned to Palbociclib, which is currently approved for estrogen receptor-positive metastatic breast cancer in combination with hormone receptor therapy.

The researchers examined more than 550 tumour biopsies from pancreatic cancer patients.

In about two-thirds, they found a protein pathway known Cdk4/6 that drives how quickly cancerous cells grow and divide.

They also showed that another protein in the Cdk4/6 pathway, RB, was present in high levels.

Mouse models showed Palbociclib worked by targeting these proteins. According to Dr Pajic, treatment increased the lifespan of the mice by an average 100 days.

"Just from seeing what happens in the clinic, we would anticipate that a population of patients with this biomarker would have exceptional responses to this therapy and then you would have more moderate responses," said Dr Pajic.

Pathologist and co-author Dr Angela Chou says having this biomarker is essential for personalised medicine, because it gives treating doctors a way to predict who is likely to respond to treatment and not.