Professor Michael Drummond pointed out that traditionally we obtain assessments of efficacy of pharmaceuticals from Phase 3 clinical trials. This is because evidence of efficacy is required for drug licensing.
The advantage of such trials is high internal validity, i.e. relative freedom from dangers of confounding bias, as compared to other forms of research. Economic evaluations, however, require evidence of effectiveness, that is outcomes as realised in regular clinical practice.
Most official guidelines for cost-effectiveness studies ask for evidence of effectiveness, which is rarely available at the time the product is first launched. Moreover, effectiveness trials are often expensive and difficult to conduct. Economists therefore often use modelling approaches to obtain estimates of cost-effectiveness outcomes from efficacy data. There has been criticism of modelling, notably from the Food and Drug Administration (DDMAC, 1995) and the New England Journal of Medicine (Kassirer and Angel, 1994). However, the report of the Public Health Service Panel (Gold et al., 1996) in the USA gave strong support to modelling approaches. Therefore, the session will explore the issues involved in moving from the assessment of efficacy to cost-effectiveness.
This OHE Briefing summarises the presentations and discussion at the session on “Efficacy to cost-effectiveness” at the Conference of the International Society for Technology Assessment in Health Care (ISTAHC) in Barcelona on 26 May 1997.
The participants were:
Professor Michael Drummond, Director of the Centre for Health Economics, University of York, UK
Dr Kevin Schulman, Director of the Clinical Economics Research Unit, Georgetown University Medical Center, USA
Professor Milton Weinstein, Henry J. Kaiser Professor of Health Policy and Management, Harvard School of Public Health, USA
Professor Bengt Jönsson, Stockholm School of Economics, Sweden