Uncertainty and the Undervaluation of Services for Severe Health States in Cost-Utility Analyses

Valuation of Treatments for Rare Diseases: A Systematic Literature Review of Societal Preference Studies

INTRODUCTION

We sought to synthesize published empirical studies that elicited and characterized societal valuations of orphan drugs and the attributes that may drive different valuations for orphan drugs versus other treatments.

METHODS

We conducted a systematic literature review (SLR) in MEDLINE and EMBASE databases up to November 2, 2020. Search terms covered societal preferences and attributes of orphan drugs (e.g., disease prevalence, severity, burden, unmet needs, and benefits).

RESULTS

We identified 38 eligible publications: 33 societal preference studies and 5 reviews discussing societal valuations and attributes of orphan drugs. Most publications suggested that a majority of respondents favored allocating funds to more prevalent diseases. However, trade-off studies and discrete-choice experiments found that survey participants chose to allocate resources to orphan drugs even when the cost per unit of health benefit was greater than for therapies for more prevalent diseases. Overall, 19 of 27 studies assessing severity in treatment valuation revealed that respondents prioritized patients with severe diseases over those with milder ones for equal health benefits. Members of the general public tended to prefer treatments for diseases with no alternative or when existing alternatives had limited efficacy over diseases with clear therapeutic alternatives. There was evidence that individuals preferred sharing resources, so no patient was left without treatment.

CONCLUSIONS

Our SLR indicates the general public typically attaches greater value to orphan drugs than to other treatments for common diseases. This is not because of rarity per se, but primarily because of disease severity and lack of therapeutic alternatives typically associated with rare diseases.

Health technology assessment (HTA) and economic evaluation: efficiency or fairness first

The economic evaluation which supports Health Technology Assessment (HTA) should inform policy makers of the value to society conferred by a given allocation of resources. However, neither the theory nor practise of economic evaluation satisfactorily reflect social values. Both are primarily concerned with efficiency, commonly conceptualised as the maximisation of utility or quality adjusted life years (QALYs). The focus is upon the service and the benefits obtained from it. This has resulted in an evaluation methodology which discriminates against groups and treatments which the population would like to prioritise. This includes high cost treatments for patients with rare diseases. In contrast with prevailing methods, there is increasing evidence that the public would prefer a fairness-focused framework in which the service was removed from centre stage and replaced by the patient. However methods for achieving fairness are ad hoc and under-developed. The article initially reviews the theory of economic evaluation and argues that its focus upon individual utility and efficiency as defined by the theory omits potentially important social values. Some empirical evidence relating to population values is presented and four studies by the first author are reviewed. These indicate that when people adopt the social perspective of a citizen they have a preference for sharing the health budget in a way which does not exclude patients who require services that are not cost effective, such as orphan medicinal products (OMP's) and treatments for patients with ultra-rare diseases (URD's).