A new study for the HSE has found that making the weight-loss drug Mounjaro available to public patients would not be value for money at the current price.
The study by the National Centre for Health Economics (NCHE) said the estimated cost per patient per year to the HSE would range from €5,526 to €6,214, depending on the dose.
The study says the drug would be cost-effective and value for money if the price was reduced by 73% for the 5 mg dose.
It estimates the five-year net drug-budget impact at the current price would range from €5.2 billion to €1.4bn, depending on the population it was prescribed for.
Mounjaro is one of a number of new blockbuster drugs for weight management - used as an adjunct for reduced calorie diet and increased physical activity - for people who are obese, or overweight and have diabetes or some other conditions.
Usually, patients need to have a body mass index of around 27-30 (kg/m2) to be prescribed the drug, along with other health considerations.
The study says that the drug has demonstrated clinically meaningful benefits in terms of weight loss and related outcomes.
Many of the so-called big blockbuster weight-loss drugs are available to private patients, costing €140-€280 or more a month.
Just one of the new weight-loss drugs - Saxenda - is covered by the HSE.
Access to Saxenda is limited to a very defined group of patients, who meet strict clinical criteria.
Around 5,000 patients are currently receiving it at an annual cost of around €14m.
There have been 24,000 applications for the prescribing of Saxenda since the start of 2023.
The demand for Mounjaro is expected to be much higher than for Saxenda, as Mounjaro is administered once a week, while Saxenda is administered once daily.
Mounjaro has also been shown to be more effective in reducing weight than Saxenda.
Other drugs like Ozempic, Trulicity and Victoza are available to eligible public patients under the Long-Term Illness Scheme for the management of type 2 diabetes.
National Centre for Pharmacoeconomics Clinical Director Professor Michael Barry said it is not unusual to get price reductions of 30-40%, meaning it is not impossible for Mounjaro to be cost effective.
Speaking on RTÉ's Morning Ireland, he said that even if it were to get to that stage, the "issue will be can we afford it?"
He said some countries in Europe do not reimburse these drugs at all, citing Germany as an example.
"And Germany is usually the one we say we'd like to be like. Germany don't reimburse it," he said.
"Other countries reimburse it partially, like ourselves, for certain subgroups. I think if it is to be reimbursed in this country it will probably be along those lines.
"But there is a policy decision to be made here - are we going to reimburse this drug or not?"
