2025-06-30 マサチューセッツ大学アマースト校
<関連情報>
- https://www.umass.edu/news/article/umass-health-economist-lucy-xiaolu-wang-finds-regulatory-transparency-curbs-patent
- https://www.sciencedirect.com/science/article/pii/S0047272725001136
販売認可と戦略的特許: 医薬品のエビデンス Marketing authorization and strategic patenting: Evidence from pharmaceuticals
Dennis Byrski, Lucy Xiaolu Wang
Journal of Public Economics Available online: 29 May 2025
DOI:https://doi.org/10.1016/j.jpubeco.2025.105415
Highlights
- Clinical trial data released in marketing authorization become prior art for patents.
- Marketing authorization reduces secondary patents, especially in same disease areas.
- Meaningful innovation remains strong with stable product and cross-disease patents.
- Originators and other firms adjust similarly in patenting; originators react sooner.
- Regulatory processes create prior art that can curb low-value follow-on drug patents.
Abstract
Patents can incentivize innovation, but pharmaceutical firms often extend market exclusivity by patenting minor modifications to existing drugs, raising concerns about low-novelty patents that add little therapeutic value. This study examines how patenting behavior changes after marketing authorization, a regulatory milestone that makes clinical trial data public and thereby creates “prior art” that limits future patent claims. Using a novel European patent–drug dataset and event study methods, we exploit plausibly exogenous variation in the time from patent priority filing to marketing authorization. We find a significant decline in strategic patenting after authorization, particularly in secondary patents and those covering the same disease areas. In contrast, follow-on product patents and patents for new disease areas remain stable, suggesting that authorization selectively curbs low-novelty filings. Both originators and other firms respond similarly, though at different speeds. The absence of similar responses after earlier milestones indicates increased difficulty in obtaining or enforcing low-value patents as the likely mechanism. Robustness checks – including alternative difference-in-differences estimators, constant exclusivity samples, and analyses accounting for non-European market incentives, firm characteristics, and instrumental variable approaches – support our conclusions. Our findings show how regulatory data transparency can indirectly improve patent quality.
