Unmet need: definitions, literature evidence and implications for HTA

The present paper illustrates the definition of unmet need provided by the peer-reviewed literature and the Health Technology Assessment (HTA) authorities across Europe in the assessment and appraisal process and within the early access schemes for medicines. The analysis relied on a descriptive review of the peer-reviewed literature and HTA documents on the definition of need (disease severity) and the way it is satisfied (existence and validity of alternatives). HTA agencies were found using (i) a narrow definition of need, focused on the clinical impact and the impact on health-related quality of life of the disease and (ii) a broad definition of comparators, including treatments used off-label in the clinical practice. Most of the contributions of the literature advocated for a broader definition of need, including additional dimensions (for example, the socio-economic impact of the disease) and the effects of existing treatments beyond their risk-benefit profile (for example, acceptability to patients). On the one hand, these contributions should be considered by HTA agencies, considering its multi-disciplinary and multi-stakeholder nature. On the other one, the explicit inclusion of the unmet need domains, at present disregarded, should depend on the decisions taken on the ground of the assessment.