Methods for the comparative evaluation of pharmaceuticals

Abstract

POLITICAL BACKGROUND: As a German novelty, the Institute for Quality and Efficiency in Health Care (Institut für Qualität und Wirtschaftlichkeit im Gesundheitswesen; IGWiG) was established in 2004 to, among other tasks, evaluate the benefit of pharmaceuticals. In this context it is of importance that patented pharmaceuticals are only excluded from the reference pricing system if they offer a therapeutic improvement. The institute is commissioned by the Federal Joint Committee (Gemeinsamer Bundesausschuss, G-BA) or by the Ministry of Health and Social Security. The German policy objective expressed by the latest health care reform (Gesetz zur Modernisierung der Gesetzlichen Krankenversicherung, GMG) is to base decisions on a scientific assessment of pharmaceuticals in comparison to already available treatments. However, procedures and methods are still to be established.

Research questions and methods: This health technology assessment (HTA) report was commissioned by the German Agency for HTA at the Institute for Medical Documentation and Information (DAHTA@DIMDI). It analysed criteria, procedures, and methods of comparative drug assessment in other EU-/OECD-countries. The research question was the following: How do national public institutions compare medicines in connection with pharmaceutical regulation, i.e. licensing, reimbursement and pricing of drugs? Institutions as well as documents concerning comparative drug evaluation (e.g. regulations, guidelines) were identified through internet, systematic literature, and hand searches. Publications were selected according to pre-defined inclusion and exclusion criteria. Documents were analysed in a qualitative matter following an analytic framework that had been developed in advance. Results were summarised narratively and presented in evidence tables.

Results and discussion: Currently licensing agencies do not systematically assess a new drug's added value for patients and society. This is why many countries made post-licensing evaluation of pharmaceuticals a requirement for reimbursement or pricing decisions. Typically an explicitly designated drug review body is involved. In all eleven countries included (Austria, Australia, Canada, Switzerland, Finland, France, the Netherlands, Norway, New Zealand, Sweden, and the United Kingdom) a drug's therapeutic benefit in comparison to treatment alternatives is leading the evaluation. A medicine is classified as a therapeutic improvement if it demonstrates an improved benefit-/risk-profile compared to treatment alternatives. However, evidence of superiority to a relevant degree is requested. Health related quality of life is considered as the most appropriate criterion for a drug's added value from patients' perspective. Review bodies in Australia, New Zealand, and the United Kingdom have committed themselves to include this outcome measure whenever possible. Pharmacological or innovative characteristics (e.g. administration route, dosage regime, new acting principle) and other advantages (e.g. taste, appearance) are considered in about half of the countries. However, in most cases these aspects rank as second line criteria for a drug's added value. All countries except France and Switzerland perform a comparative pharmacoeconomic evaluation to analyse costs caused by a drug intervention in relation to its benefit (preferably by cost utility analysis). However, the question if a medicine is cost effective in relation to treatment alternatives is answered in a political and social context. A range of remarkably varying criteria are considered. Countries agree that randomised controlled head-to-head trials (head-to-head RCT) with a high degree of internal and external validity provide the most reliable and least biased evidence of a drug's relative treatment effects (as do systematic reviews and meta-analyses of these RCT). Final outcome parameters reflecting long-term treatment objectives (mortality, morbidity, quality of life) are preferred to surrogate parameters. Following the concept of community effectiveness, drug review institutions also explicitly favour RCT in a "natural" design, i.e. in daily routine and country specific care settings. The countries' requirements for pharmacoeconomic studies are similar despite some methodological inconsistencies, e.g. concerning cost calculation. Outcomes of clinical and pharmacoeconomic analyses are largely determined by the choice of comparator. Selecting an appropriate comparative treatment is therefore crucial. In theory, the best or most cost effective therapy is regarded as appropriate comparator for clinical and economic studies. Pragmatically however, institutions accept that the drug is compared to the treatment of daily routine or to the least expensive therapy. If a pharmaceutical offers several approved indications, in some countries all of them are assessed. Others only evaluate a drug's main indication. Canada is the only country which also considers a medicine's off-label use. It is well known that clinical trials and pharmacoeconomic studies directly comparing a drug with adequate competitors are lacking - in quantitative as well as in qualitative terms. This is specifically the case before or shortly after marketing authorisation. Yet there is the need to support reimbursement or pricing decisions by scientific evidence. In this situation review bodies are often forced to rely on observational studies or on other internally less valid data (including expert and consensus opinions). As a second option they use statistical approaches like indirect adjusted comparisons (in Australia and the United Kingdom) and, commonly, economic modelling. However, there is consensus that results provided by these techniques need to be verified by valid head-to-head comparisons as soon as possible.

Conclusions: In the majority of countries reimbursement and pricing decisions are based on systematic and evidence-based evaluation comparing a drug's clinical and economic characteristics to daily treatment routine. However, further evaluation criteria, requirements and specific methodological issues still lack internationally consented standards.