In the pharmaceutical industry, maintaining market exclusivity is crucial for companies looking to maximize the return on their investments in drug development. This article delves into the concept of evergreening, a strategy used by pharmaceutical companies to extend the commercial lifecycle of their products. We will explore various techniques used in evergreening, its implications, and the ethical and legal debates surrounding it.
What is Evergreening?
Evergreening refers to the practice of making slight modifications to existing drugs and re-patenting them to extend their market exclusivity. This strategy is often employed as the original patent nears expiration. Evergreening can involve changes in the formulation, method of administration, dosage, or combination with other drugs. The intent is to delay the entry of generic competitors, thereby preserving the revenue stream for the patented drug.
Techniques of Evergreening
Formulation Changes: A common strategy involves altering the drug’s formulation, which can include developing a new delivery system (like transdermal patches or inhalers), creating extended-release versions, or changing the drug’s composition to improve stability or efficacy.
New Indications: Seeking approval for new therapeutic uses of a drug can extend its patent life. This involves conducting clinical trials to prove the drug’s efficacy in treating additional conditions. This not only extends the patent life but also broadens the market for the drug.
Combination Therapies: Combining an existing drug with one or more other active ingredients can lead to a new patent, even if the original drugs are already well-known.
Chiral Switching: Some drugs exist as mixtures of isomers. Separating these and using only the active isomer can create a new patentable drug.
Patenting Metabolites or Polymorphs: Sometimes, metabolites (substances produced when the body breaks down the drug) or different crystalline forms of a drug (polymorphs) are patented as new inventions.
Economic and Clinical Impacts
The practice of evergreening has significant economic impacts. It allows pharmaceutical companies to maintain high prices for their drugs, as generic competition is delayed. This can lead to increased healthcare costs for both patients and healthcare systems.
However, some evergreening strategies lead to genuine clinical improvements, such as reduced side effects, increased efficacy, or more convenient dosing schedules. These benefits can improve patient adherence and outcomes.
Ethical and Legal Considerations
Evergreening is a controversial practice. Critics argue that it prioritizes profits over patient access to affordable medications. In response, many countries have implemented legal measures to limit evergreening practices, requiring companies to prove significant clinical benefits of new patents over existing drugs.
Conversely, proponents of evergreening argue that it incentivizes innovation and the development of better drugs. The pharmaceutical industry also emphasizes that patent protections are essential for recouping the substantial costs involved in drug research and development.
Further Reading
For those interested in exploring this topic further, several articles highlight the nuances of evergreening:
Drug patents: the evergreening problem – Roger Collier – Canadian Medical Association Journal
Combination therapy patents: a new front in evergreening – Strohbehn, G.W., Kacew, A.J., Goldstein, D.A. et al. Combination therapy patents: a new front in evergreening. Nat Biotechnol
Additionally, several resources offer in-depth perspectives on evergreening:
Pharmaceutical Patent Law Book: This book provides a comprehensive overview of pharmaceutical patent law, including chapters on evergreening.
Journal of Medical Ethics: Contains articles discussing the ethical implications of evergreening in the pharmaceutical industry.
Evergreening is a complex and multifaceted. While it can lead to improvements in drug therapy, it also raises significant ethical and economic concerns. As the industry evolves, it is crucial for professionals to understand evergreening’s implications for healthcare, legal landscapes, and pharmaceutical innovation.