Estimating the impact of biosimilar entry on prices and expenditures in rheumatoid arthritis: a case study of targeted immune modulators

Abstract

Objective

To model changes in prices, utilization, and expenditures of targeted immune modulators (TIMs) for rheumatoid arthritis, accounting for biosimilar entry.

Methods

Using IQVIA National Sales Perspective data between 2013 and 2019, we examined sales and expenditures of biologics and non-biological complex molecules, 20 quarters before and after patent exclusivity milestones. We estimated the impact of a molecule’s exclusivity milestones and biosimilar entry on prices, using a regression discontinuity design (RDD). We then combined the RDD estimate with historical trends to assess the impact of adalimumab’s exclusivity milestones on future TIM expenditures.

Results

Changes in average molecule prices were associated largely with biosimilar uptake. For molecules with relatively high biosimilar uptake (>60%), prices fell considerably (−21.2% to −59.3%) one year after exclusivity milestones, whereas molecules with lower biosimilar uptake (<10%) experienced smaller price decreases (−2.4% to −8.4%). Average price reduction at the molecule level after biosimilar entry was not significant (−18.6%; p = .657). When applying the RDD results after adalimumab’s exclusivity milestones, its projected share of total TIM market expenditures decreased from 48.0% in 2019 to 26.0% in 2025, whereas expenditures on Janus kinase inhibitors increased from 4.0% to 34.0%.

Conclusions

Biologics facing biosimilar competition may experience price decreases, potentially offering substantial savings to payers, patients, and society, although the magnitude of these estimates depends on biosimilar uptake. Formulary placement, along with manufacturer-payer dynamics, may also play a role in determining the impact on price and market uptake of biosimilars.

Keywords:

• Biologics
• biosimilars
• tumor necrosis factor inhibitors
• Janus kinase inhibitors
• adalimumab
• etanercept

JEL codes:

• C53
• C5
• C
• C54
• C55

Transparency

Declaration of funding

The study was sponsored by Amgen Inc.

Declaration of financial disclosures

MH was an employee and stockholder of Amgen Inc., at the time of conduct of this study; MG and AP are employees of PRECISIONheor, which received financial support from Amgen Inc., for the conduct of this study. At the time of the conduct of this study, JS was an employee of PRECISIONheor, which received financial support from Amgen Inc. for the conduct of this study.

Author contributions

Conception/design of the study: EJMH, JS, MG. Acquisition, analysis, or interpretation of data: JS, MG, AP. Drafting and revising: EJMH, JS, MG, AP

Acknowledgements

Julie Wang, of Amgen Inc., and Lakshmi Narendra Bodduluru, of Cactus Life Sciences (part of Cactus Communications) provided editorial assistance for this manuscript, funded by Amgen Inc.

Data availability statement

The datasets generated and/or analyzed during the current study are available from the corresponding author on reasonable request.

Reviewer disclosures

A reviewer on this manuscript has disclosed that they have provided contractual, advice and analysis for Amgen Canada Inc. (not in this space). The other peer reviewers on this manuscript have no other relevant financial relationships or otherwise to disclose.