Systematic bias in predictions of new drugs’ budget impact: analysis of a sample of recent US drug launches

Abstract

Objective: Expectations about the budget impact of new drug launches may affect payer behavior and ultimately consumer costs. Therefore, we evaluated the accuracy of pre-launch US budget impact estimates for a sample of new drugs.

Methods: We searched for publicly available budget impact estimates made pre-launch for drugs approved in the US from 1 September 2010 to 1 September 2015 and compared them to actual sales. Accuracy was calculated as the ratio of pre-launch estimate to actual sales. Quantitative analyses, including multivariate regressions, were used to identify factors associated with accuracy.

Results: We identified 25 budget impact estimates: 23 for one of 14 individual drugs and 2 for the category of PCSK9 inhibitors. The ratios of predicted to actual budget impact ranged from 0.2 (estimate was 20% of sales) for secukinumab to 37.5 (estimate was 37.5 × sales) for PCSK9 inhibitors. Mean ratio was 5.5. In multivariate analyses, larger eligible population, more recent estimate year (e.g. 2015 vs. 2012), and being first in class, were associated with statistically significant, greater overestimation of budget impact.

Conclusions: For every $5.5 of predicted cost, there was $1 of actual cost to the healthcare system. This study, although based on a small, non-random sample, suggests possible cognitive bias on the part of the estimators. Overestimating budget impact may lead to early access restrictions, higher copays, and other changes that ultimately impact patients. Analysts and non-profits should be attuned to likely sources of error in order to improve their predictions.

Keywords:

• Pharmaceutical sales
• healthcare expenditures
• accuracy
• forecast
• budget impact estimate

Transparency

Declaration of funding

This study was funded by Amgen.

Author contributions: All authors were equally involved in the design of the study. R.S.M. conducted the statistical analyses and all authors contributed equally in the interpretation of results and writing of the manuscript.

Declaration of financial/other relationships

M.S.B., J.M.Z., and J.L. have disclosed that they are employees of Partnership for Health Analytic Research LLC, a health services research company paid by Amgen to conduct this research. R.S.M. has disclosed that he has no significant relationships with or financial interests in any commercial companies related to this study or article.

CMRO peer reviewers on this manuscript have no relevant financial or other relationships to disclose.

Previous presentations: An earlier version of this analysis was presented at Academy of Managed Care Pharmacy NEXUS, 3–6 October 2016.

Acknowledgements

No assistance in the preparation of this article is to be declared.