A clinical trial of a new combination of two drugs which it's hoped can treat advanced breast cancer that has not responded to currently available treatment has begun here.

Up to 34 patients with progressed or recurred HER2+ advanced breast cancer will be involved in the trial that will take place over the next 3 years.

The research will examine whether a new drug called copanlisib can effectively combat advanced cases of the cancer when it is mixed with another compound, trastuzumab.

Patients with HER2+ over-produce a protein that stimulates cancer cell growth.

Existing treatments, including trastuzumab, can slow down or sometimes stop the growth.

But resistance can occur, rendering such medicines useless.

According to consultant oncologist Professor Bryan Hennessy, Clinical Lead at Cancer Trials Ireland, the hope is that copanlisib given alongside trastuzumab could reverse that resistace.

That's because it blocks the unusual activity in the pathway of  a specific gene which mutates, causing the resistance.

The trial will cost around €750,000 and will be sponsored by Cancer Trials Ireland and Bayer Healthcare.

Beaumont Hospital in Dublin, St Vincent's University Hospital in Dublin, St. James's Hospital in Dublin, University Hospital Galway and Cork University Hospital are the hospitals where the trial will be carried out.