The concept of Willingness to Pay (WTP) was explained in an earlier blog. However, the Belgian KCE guidelines, which have applied since April 2025, do not refer to a WTP threshold. The underlying rationale is that the government (NIHDI) wishes to assess for itself whether a technology is cost-effective, without relying on an explicit WTP threshold. As a result, Belgium- like several other countries- does not have an official WTP. For this reason, the price of a technology cannot formally be determined or justified on the basis of cost‑effectiveness alone.

Nevertheless, as consultants we observe that a (net) price is often aligned with a WTP of €40,000 per gained QALY. Over the years, we have seen this unofficial WTP evolve from €30,000 to €40,000, but without any guarantee that a technology will be reimbursed if the WTP is below €40,000 per gained QALY.

As consultants, we argue in favour of clear regulations. Conducting health-economic analyses without a WTP is comparable to sailing at sea without navigation: you move forward, but you do not really know whether you will reach your intended destination. The value of a cost‑effectiveness analysis only becomes meaningful if cost‑effectiveness can be claimed on the basis of a WTP.

On the other hand, we also understand the government’s position. In principle, it should not be the intention that the list price of a new technology is set on the basis of the WTP – in other words, that the list price is artificially increased until it just falls below the WTP and therefore still remains cost‑effective. It seems sensible to us to set a list price based on actual costs plus an acceptable profit margin.

However, perhaps the price should not be adjusted based on the WTP, but rather the WTP itself could, in our view, be set variably based on several parameters.

One possible methodology would be to set a WTP as a function of disease burden and the number of remaining life years. It is, of course, nearly impossible to define a separate WTP for each indication. But recognized medical need could be used to determine the WTP threshold – or, put differently: the higher the medical need, the higher the willingness to pay. The list of recognized unmet medical needs (UMN) is reviewed annually, and since 2026 there has also been the possibility of obtaining (limited) reimbursement prior to EMA registration. We refer to our previous blog for more information on this topic (early access).

However, if the unofficial WTP is maintained, we believe it should be updated over the time horizon. The €40,000 of “today” will be worth less in 10 years’ time. Future inflation is therefore an important parameter to take into account. The current KCE guidelines are specific with regard to discounting: costs should be discounted at 3% per year and health effects at 1.5% if the time horizon exceeds one year. But if discounting must be taken into account, then the WTP should also evolve over time.

A simple example helps to illustrate this:

If a technology today costs €20,000 per year and results in a health gain of 0.5 QALYs, this corresponds to €40,000 per gained QALY. In 10 years, the cost would be €26,878 (= €20,000 × (1+0.03)¹⁰). The health gain would likewise have evolved to 0.58 (= 0.5 × (1+0.015)¹⁰). Taking the ratio of these two figures results in an incremental cost‑effectiveness ratio of €46,320 per gained QALY—in other words, the WTP would need to increase to €46,320 after 10 years.

Could a proportional factor be applied where the discounting of costs and health gains is captured in a single percentage? Absolutely: 1.03 / 1.015 = 1.0148, or 1.478% per year.

Applying this type of discounting would allow companies and governments to take into account additional innovation and financial corrections based on inflation. In parallel, companies would uniformly apply a comparable WTP, thereby providing greater clarity – also for the government.

An additional element is that specialty products marketed via a managed entry agreement should not be required to remain fixed at the temporarily established list (and/or net) price. In other words, as long as the price is not final, the government should take into account updated costs subject to inflation (raw materials, distribution, wages, etc.). Introducing a dynamic WTP that evolves over time is therefore HEBIAS’s recommendation to current policymakers and, in our view, would support developers in bringing innovation to market.