Adalimumab Expenditures in Countries With and Without Available Biosimilars

A recent study used difference-in-difference analysis to assess adalimumab sales volumes and expenditures in 6 countries with available biosimilar adalimumab products and 8 countries without.In countries with adalimumab biosimilars, the authors reported adalimumab expenditures decreased while consumption was maintained or increased. Based on their findings, the introduction of adalimumab biosimilars is expected to result in budget savings of $371 per gross domestic product (GDP) per capita during the first year, alongside an increase of 1.0 standard units (SU) in treatment accessibility per 1000 population.

According to the authors, few previous studies have investigated whether the introduction of adalimumab biosimilars was associated with budget savings, and whether those savings were achieved through lower adalimumab prices, changes in adalimumab consumption, or increased utilization of biosimilars (drug mix).

The reference adalimumab (Humira), a tumor necrosis factor (TNF)-α inhibitor, was first approved by the FDA in 2002 and the European Medicines Agency (EMA) in 2003. It was the highest-selling biologic worldwide by 2018. In 2018, the authors noted, global sales of TNF inhibitors was $40 billion, with Humira accounting for half, $20 billion, of that total. Following the expiration of Humira’s patent in Europe in 2018, 5 biosimilars were introduced. Adalimumab biosimilars were also introduced in Brazil and South Africa in 2020; Australia, Japan, and the Republic of Korea in 2021; Canada in 2022; and the United States in 2023.

Their study assessed the influence of biosimilar availability on adalimumab expenditures in 14 high- and upper-middle-income countries, based on data from the Multinational Integrated Data Analysis System IQVIA database from October 2018 to October 2019. During this study period, adalimumab biosimilars were available in 6 countries: Austria, France, Germany, Italy, Spain, and Sweden. The authors compared adalimumab expenditures in these countries to 8 countries in which adalimumab biosimilars were not available: Australia, Japan, the Republic of Korea, Singapore, Taiwan, Canada, South Africa, and Brazil.

Over the 4 quarters covered by the study period, in countries with adalimumab biosimilars, overall there was a significant decrease in spending of –$371 per gross domestic product (GDP) per capita, ranging from –$1113 per GDP per capita in Spain to –$57 per GDP per capita in Sweden. All countries with available biosimilars showed a decrease in adalimumab expenditure, with the exception of Italy where spending on adalimumab increased by $0.1 per GDP per capita.

The investigators observed the opposite trend in countries without adalimumab biosimilars. Adalimumab sales value per GDP per capita increased in most of these countries, ranging from $0.7 per GDP per capita in Singapore to $213 per GDP per capita in Canada, with the exception of Brazil where spending on adalimumab decreased by $162 per GDP per capita.

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The decrease in expenditure in countries with available adalimumab biosimilars was observed alongside increases in adalimumab consumption. Sales volume increased in all countries with biosimilars, ranging from 0.2 SU per 1000 population in France to 3.2 SU per 1000 population in Sweden.

In countries without biosimilars, adalimumab sales volume per 1000 population “either decreased or showed minimal growth,” the authors said. Changes in sales volume ranged from –0.01 SU per 1000 population in Brazil to 0.1 SU per 1000 population in Taiwan.

According to their findings, the authors said there was 14% decrease in expenditures in countries with available adalimumab biosimilars due to 2 factors: lower prices for adalimumab due to the availability of biosimilars, and the drug-mix effect, substituting more expensive with less expensive adalimumab products. In contrast, changes in adalimumab expenditure in countries without available biosimilars “changed in a quantity-dependent manner,” with increases in expenditure associated with increased adalimumab consumption.

Although biosimilars offer cost savings, the authors said, the potential benefits of biosimilars are “realized differently across various jurisdictions due to diverse healthcare systems and government policies.” They cited previous research suggesting that countries implementing supply-side policies, such as Austria, tend to experience price reductions, whereas countries implementing demand-side policies, such as Germany, tend to realize budget savings due to higher penetration of biosimilars. They noted their results were consistent with this research, finding that Austria achieved the highest price reduction (60%) among countries with adalimumab biosimilars and the highest drug mix effect was found in Germany.

The authors concluded the availability of adalimumab biosimilars was associated with a decrease in expenditures “without compromising the consumption of adalimumab,” with price reduction and the drug mix effect as major contributors. They added that their findings “highlight the importance of introducing biosimilars and balancing demand-side and supply-side policies as a strategy to optimize healthcare expenditure and ensure patient access to essential treatments.”

Reference

Woo H, Shin G, Lee D, Kwon HY, Bae S. Is the availability of biosimilar adalimumab associated with budget savings? A difference-in-difference analysis of 14 countries. BioDrugs. 2024;38(1):133-144. doi:10.1007/s40259-023-00636-z