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Updated: Sep 23, 2025

Drug Repurposing Hypothesis Generation Using the "RE:fine Drugs" System
Published on: December 11, 2016
Evergreened drugs or evergreened profits?
Simran Siddalingaiah1, Adriane Fugh-Berman1
1Department of Pharmacology and Physiology, Georgetown University Medical Center, Washington, District of Columbia, USA.
Background:
Branded drugs contribute disproportionately to high prescription drug spending. Pharmaceutical companies utilize patent extension "evergreening" techniques that contribute to high drug costs.
Aims:
This article describes various patent extension techniques and analyzes the tactic of combining generic drugs with branded drugs, using metformin combinations for diabetes treatment as a case study. It examines the argument that FDCs enhance adherence and compares the cost of several branded fixed-dose combinations with the cost of their individual constituents.
Materials & Methods:
We reviewed literature on patent extension techniques in both medical and marketing literature, supplemented by our own extensive files. We performed a price analysis of several branded pharmaceuticals and generically available equivalents. Prescription drug prices were determined using GoodRx.com, and prices of over-the-counter products were established based on the prices of two chain wholesalers. Patent and formulation information was taken from the FDA Orange Book: Approved Drugs with Therapeutic Equivalence Evaluations database.
Results:
"Evergreening" patent extension tactics include the sequential release of different formulations, minor dosing changes, and fixed-dose combinations (FDCs). A "new use" provides an opportunity for a company to re-patent, rebrand, and remarket one drug for multiple indications. It is unclear whether or not FDCs enhance adherence. Branded fixed-dose combinations generally cost far more than their individual constituents. FDCs that combine metformin with other drugs are an exception, often costing the same as the non-metformin component.
Discussion:
Patent extension tactics increase drug costs while providing little additional benefit to patients. Minor alterations in formulations or dosing may provide no clinical benefits. Many FDCs are expensive and fail to provide cost-justified improvements in clinical outcomes, compared to equivalent generic drugs that would save money while delivering an equal standard of care. Combining newer hypoglycemic drugs with metformin, a gold-standard, generic, inexpensive drug, does not appear to cost more than individual constituents but offers no clinical advantage over metformin alone.
Conclusion:
Evergreening tactics should be reined in, as they represent significant cost to the healthcare system and to patients. Physicians and other prescribers should avoid prescribing FDCs, or slightly tweaked "new" drugs. Patented drug combinations generate profit without innovation.
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