Publication Date

5-21-2026

Abstract

Introduction Our study examines modification patents across multiple New Drug Applications (NDAs), employed by pharmaceutical companies to extend patent protections. Ours is the only comprehensive study of modification patents by Active Pharmaceutical Ingredient (API) across multiple NDAs, the approach of current regulatory initiatives, investigating how these patents extend drug protections and impede generic entry.

Methods We examine 1028 modification patents, categorizing them as chemical variations, formulation changes, treatment methods, or device/agent. We tabulated additional granted protection time, correlations with new NDAs, and litigation from potential generics.

Results On average, 5 modification patents protected each drug, extending granted protection periods by 10.9 years. Examining market outcomes for the 199 drugs with generics approved by August 2025, or whose primary patents had expired by then, modification patents provided a median of 2.3 years' median effective additional protection time before generic entry. Eighty-nine percent of drugs' protection periods were extended by modification patenting in some dimension. Fifty-eight percent had a modification patent associated with a new NDA, and 70% had at least 1 modification patent in Paragraph IV-related litigation.

Conclusion These findings suggest we reconsider societal resources dedicated to modification patenting, generally and during clinical decision-making. Hope for regulatory and legislative reform lies in a “one-and-done” policy and restricting certain patent types.

Document Type

Article

Publication Title

Health Affairs Scholar

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