New Blood Test Could Quickly Predict If Drug Palbociclib Will Work in Breast Cancer Patients

New blood test for cancer DNA developed by scientists could predict if a woman is responding to new breast cancer drug palbociclib, months earlier than current tests.

New blood test could detect in two to three weeks whether the drug palbociclib works in patients with breast cancer, revealed scientists from The Institute of Cancer Research, London, and The Royal Marsden NHS Foundation Trust. The scientists also caution that the results need replicating before they are used clinically.

The research, published today in the journal Nature Communications, was largely funded by the Medical Research Council (MRC). The researchers tested women with oestrogen receptor positive breast cancer - the most common kind - who were taking part in a clinical trial of palbociclib for advanced breast cancer.

Breast Cancer Screening using Mammogram
Breast cancer if detected early can be completely cured. Mammography is used to screen women for breast cancer.

‘New blood test for cancer DNA developed by scientists could predict if a woman is responding to new breast cancer drug palbociclib, months earlier than current tests.’

In November 2017, palbociclib was approved for use on the NHS by NICE for women with previously untreated advanced breast cancer.

Currently, women must wait two to three months to find out, using a scan, if palbociclib is working.

The new blood test instead looks for circulating tumour DNA - fragments of DNA shed by the cancer that have entered the bloodstream. The DNA mutations associated with the cancer can be detected in these samples.

Palbociclib
Palbociclib is a kinase inhibitor which is prescribed along with letrazole (an aromatase inhibitor) for the treatment of certain type of hormone receptor positive breast cancer (estrogen receptor (ER)-positive, human epidermal growth factor receptor 2 (HER2)-negative breast cancer) in postmenopausal women that is in an advanced stage or has spread to other parts of the body. It is also used along with fulvestrant in women in whom the cancer continues to worsen despite hormonal treatment. Palbociclib blocks the action of a specific protein that plays a role in the multiplication of cancer cells.

The researchers found that they could predict if the palbociclib treatment would work by comparing the amount of a gene PIK3CA detected in a blood test before treatment and 15 days after starting treatment. In the study, 73 women had the PIK3CA mutation and were given blood tests before and after starting palbociclib treatment.

In these women, the researchers found that those who had a small decrease in PIK3CA circulating DNA at 15 days had a median progression-free survival (the length of time the patient survived and the cancer did not get worse) of only 4.1 months, compared with women with a large decrease in PIK3CA, who had a median progression-free survival of 11.2 months.

Breast Cancer Risk Assessment Calculator
Breast Cancer Risk Assessment Calculator predicts the risk for breast cancer. Find list of breast cancer facts and more information on signs and symptoms of breast cancer and mammography.

The test could allow the women in the first group for whom the treatment is not as effective to be identified early and they could consider altering their treatment.

Professor Nicholas Turner, senior author and Professor of Molecular Oncology at The Institute of Cancer Research, London, and Consultant Medical Oncologist at The Royal Marsden NHS Foundation Trust, said: "Palbociclib is one of a new class of drugs that delays cancer progression for patients with advanced breast cancer, but it's not effective for everybody. The problem is we have to wait for two to three months before doing a scan to see if the therapy is working. Our new study found that a blood test for cancer DNA in the first two weeks of treatment indicated whether the drug was likely to be effective. Having an early indication of how likely a treatment is to work might allow us to adapt treatment - switching some patients to an alternative drug that is more likely to benefit them."

Quiz on Breast Cancer
Breast cancer is one of the leading causes of cancer deaths among women. It is often said that a woman who breast-feeds is at a lower risk of developing cancer compared to another who does not .Are these mere old wives tales or is there some truth in it? This quiz on breast cancer has all the details.

Dr Nathan Richardson, Head of Molecular and Cellular Medicine at the MRC, said: "It is exciting to see that using advances in diagnostic techniques, such as genetic tests for circulating tumour DNA, we may be able to more accurately define groups of patients and help us deliver the right treatment to the right patient sooner. This study provides early evidence that might help us understand sooner when a drug is successfully treating breast cancer, and if not, it can be discontinued and better approaches pursued."

The research also received funding from the charity Breast Cancer Now and the pharmaceutical company Pfizer.

Source-Eurekalert