The determinants of cost-effectiveness potential: an historical perspective on lipid-lowering therapies

The concept of cost effectiveness emerged in an attempt to link the prices of new healthcare technologies to the immediate value they provide, with payers defining the acceptable cost per unit of incremental effect over the alternatives available. It has been suggested that such measures allow developers to assess potential market profitability in an early stage of development, but may result in discouraging investment in efficient research if not used appropriately.

The objective of this study is to identify the pattern of the factors determining cost effectiveness and assess the evolution of cost-effectiveness potential for drugs in development using lipid-lowering therapy as a case study.

The study is based on observational clinical and market data covering a 20-year period (from 1990 to 2010) in the UK. Real-life clinical data including total cholesterol laboratory test results were extracted from the Clinical Practice Research Datalink (CPRD) and are used to illustrate how the clinical effectiveness of existing standard care changed over time in patients managed in clinical practice. Prescription Cost Analysis (PCA) data were extracted and the average price of the drug mix used was computed throughout the study period. Using this information, the maximum clinical benefit and cost savings to be had were estimated for each year of the analysis using a cost-effectiveness model. Subsequently, the highest price a new technology providing the maximum clinical effectiveness possible (i.e. eliminating cardiovascular risk from high cholesterol levels) could achieve under current cost-effectiveness rules was calculated and used as a measure of the potential cost effectiveness of drugs in development.

The results in this study show that the total cholesterol values of patients managed in clinical practice moved steadily towards recommended clinical targets. Overall, the absolute potential for incremental health-related quality of life decreased by approximately 78 %, contracting from 0.36 QALYs to 0.08 QALYs, which resulted in a saving of approximately 15 % of the costs related to cardiovascular events. The price of the drug mix used in the management of high blood cholesterol varied considerably across the years: the weighted average monthly price (in year 2007 values) started at approximately £14, peaked around £26 and progressively decreased to its minimum at £6.85 in 2010. As a consequence, the maximum price allowed by current cost-effectiveness rules for a new technology achieving the clinical target was found to decrease by a minimum of 80 % between 1990 and 2010.

The analysis supports the hypothesis that the potential for cost effectiveness of new therapies is dependent on factors specific to each disease area and furthermore to sub-populations within disease areas. Despite a clinical need still existing, the results suggest that no more technologies are likely to be developed in certain disease areas based on their low perceived cost-effectiveness potential. This occurs without considering the immediate and future value of the effectiveness lost, which may depend on the technical difficulty of materializing future advancements, and ignores the permanent character of such a decision. The analysis suggests that a single, static and arbitrary cost-effectiveness threshold may not be sufficient to capture the drug-development dynamics occurring at the disease level and successfully direct research to the disease areas that are most valued by society.