The head of the National Centre for Pharmaco-Economics, which advises the Health Service Executive on drug costs, has said he believes a breast cancer drug the centre has rejected at its current cost will ultimately be made available to patients.

The centre has advised the HSE to reject the drug Kadcyla, manufactured by Roche, on the basis that at a price of €80,000 per course of treatment it is not cost effective.

Speaking on RTÉ's Morning Ireland, Professor Michael Barry, head of the centre, said there were no doubts about some of the benefits from this drug.

However, the centre concluded that the drug was not cost-effective at the proposed price.

Prof Barry said there would now be a discussion on the price.

He said there was a price at which it would be cost-effective, and he said the centre had made that information available to the HSE.

"We concluded that it wasn't cost effective at that price. Which means of course that there is a price where it would be cost-effective and we know that price, and we have made that information available to the HSE.

"We're not saying the drug shouldn't be made available. We're just saying that at this price. It means that there is a price where it should be made available.

"And that's really where the next step goes. There's a discussion on price."

Prof Barry said the next phase would be negotiating around the price, which he said very often resulted in reductions of about 10-20%.

He said he was "pretty optimistic" that the drug would be made available to patients.