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Trial confirms way to slow cancer

Dr Janice Walsh, the Principal Investigator on the Paloma-2 trials discusses the results on RTE (13th December)

An international cancer trial, in which Cancer Trials Ireland has had a lead role, has confirmed a treatment that can significantly reduce the risk of the cancer progressing in women with advanced breast cancer.

The PALOMA-2 trial confirmed that the new drug palbociclib taken with the standard hormone therapy letrozole slows the progress of cancer among postmenopausal women with advanced (ER-positive, HER2-negative) breast cancer

The results of the trial have been published in the New England Journal of Medicine http://www.nejm.org/doi/full/10.1056/NEJMoa1607303.

Dr Janice Walshe, Consultant Medical Oncologist at St. Vincent’s University Hospital and Tallaght Hospital, is the Principal Investigator of the Irish arm of the trial and is one of the article’s authors. 

Dr Walshe said the findings were highly significant for women with breast cancer which has spread to other parts of their bodies.

”These are very exciting break through findings and have set a new standard for the treatment of this kind of breast cancer”, Dr Walshe said.

“Our trial found that this combination of palbociclib and letrozole slowed the rate of cancer cell growth.

“For patients on the combination, cancer cells stopped growing for just over two years (median 24.8 months). This compared with 14.5 months for patients taking the standard care drug letrozole alone. That’s a 42% increase in the amount of time without cancer growth.

“This finding means that the need for women with this type of cancer to start chemotherapy could be delayed.

“This is unprecedented for this patient population and is a material step forward. Breaking this 2 year barrier is highly significant,” Dr Walshe said.

Palbociclib is a class of drug known as a CDK (cyclin-dependent kinase) inhibitor. It works by blocking the proteins called CDK 4 and 6 in cancer cells. Blocking these proteins interferes with the ability of the cancer cell to grow, divide, repair and/or communicate with other cells. 

PALOMA-2 is a randomized double-blind Phase 3 trial and involved a total of 666 women who had not had prior treatment for advanced disease from 186 global centres in 17 countries. 22 patients in Ireland were enrolled on the trial and 17 are still receiving treatment on the trial. The trial was funded by Pfizer. It will continue up to 2018 to determine if this combination has an effect on the overall survival of patients.

Breast cancer is the most common invasive cancer among women in Europe, with more than 464,200 new cases and 131,260 deaths per year. Up to 30 percent of women diagnosed with and treated for early breast cancer will go on to develop metastatic breast cancer which occurs when the cancer spreads beyond the breast to other parts of the body.

Cancer Trials Ireland is supported by the Health Research Board and the Irish Cancer Society.