Understand patent evergreening—how companies extend patent life, its regulation under Section 3(d) in India, global comparisons, and its impact on innovation and public health.

What Is Patent Evergreening?

“Patent Evergreening” refers to strategies used by patent holders—especially in pharmaceuticals—to extend patent protection beyond the standard 20 years. This is done by filing new patents for slightly modified versions of the original invention.

Though legally permitted in many countries, it’s controversial for delaying generic drug entry, impacting public health and pricing.

What Qualifies as Patent Evergreening?

Evergreening typically involves minor improvements or variations of an existing invention, such as:

• A new salt form of a drug

• A slow-release formulation

• A combination with another drug

• A different method of administration

• A different dosage or concentration

Patent Evergreening in India: Restricted Under Law

Section 3(d) – The Anti-Evergreening Provision

“The mere discovery of a new form of a known substance which does not result in the enhancement of the known efficacy... is not patentable.”

This clause was added in 2005 to the Indian Patents Act, 1970—primarily to prevent evergreening and promote access to affordable medicines.

Real-World Examples of Evergreening

Rejected Evergreening (India)

1. Novartis’ Glivec (Imatinib Mesylate)

• Novartis sought a patent for a beta crystalline form of Glivec, claiming better stability.

• The Supreme Court held that the new form lacked enhanced therapeutic efficacy.

• Patent denied under Section 3(d).

2. Roche’s Valganciclovir

• The Delhi High Court revoked the patent on grounds of lack of novelty and inventive step.

• It was considered an attempt to evergreen the known antiviral Ganciclovir.

3. Pfizer’s Sutent (Sunitinib)

• Pfizer applied for a polymorph form of an existing compound.

• Rejected by the Indian Patent Office for failing to show enhanced efficacy.

✅ Approved Evergreening (Outside India)

1. Pfizer’s Lipitor (Atorvastatin) – USA

• Pfizer extended protection by patenting:

• A calcium salt form

• A tablet formulation

• Methods of treatment

• Delayed generics by filing over 40 patents.

• Generated billions in additional revenue before expiration.

2. AstraZeneca’s Nexium (Esomeprazole) – USA & EU

• A follow-up to Prilosec (Omeprazole) using an enantiomer.

• Although therapeutically similar, AstraZeneca obtained a new patent for the S-isomer.

• Kept competitors off the market for years.

3. GSK’s Advair Diskus – USA

• GSK filed multiple device and formulation patents after the original compound patent expired.

• Extended protection for years through device + method combination patents.

Patent Evergreening Laws Around the World

Conclusion: Strategic Innovation vs. Evergreening

Evergreening can blur the line between genuine innovation and legal monopoly abuse. While countries like the US and EU allow it through various mechanisms, India stands firm against evergreening via Section 3(d).

Innovators should focus on substantive improvements, not just patent layering, to avoid rejections and build a credible IP portfolio.

For Indian companies eyeing international patents, understanding evergreening norms globally is essential for strategic filings and risk mitigation.

Frequently Asked Questions (FAQs)

Q1. Is evergreening illegal in India?
👉 It’s not “illegal,” but it is prohibited if it doesn't show enhanced efficacy under Section 3(d).

Q2. Can Indian pharma companies evergreen their patents abroad?
👉 Yes, in countries like the US or EU, provided the filing meets patentability requirements there.

Q3. What’s the difference between a continuation patent and evergreening?
👉 Continuation filings are legitimate extensions or refinements of an application. Evergreening often implies repetitive minor changes without inventive step.

Q4. Is evergreening only relevant in pharma?
👉 No. It’s most visible in pharma, but the strategy is sometimes seen in tech and chemicals too.

Q5. How can I avoid Section 3(d) issues?
👉 Work with patent experts who can:

• Draft clear claims showing efficacy

• Provide comparative data

• Align filings with regulatory approvals