DOCTRINE OF EQUIVALENTS IN INDIA

The Doctrine of Equivalents (DoE) is a principle in patent law that allows a court to find infringement even if the allegedly infringing product or process does not fall within the literal wording of the patent claims, provided it performs substantially the same function in substantially the same way to achieve the same result.

Key Idea:

Literal infringement ≠ only basis for patent protection. Slight modifications or substitutes that perform the same function in the same way may still infringe.

1. Statutory Context in India

Indian Patents Act, 1970, does not explicitly mention the Doctrine of Equivalents.

Section 48 and Section 104 provide for exclusive rights and remedies for infringement, which courts have interpreted to allow DoE application.

Indian courts often refer to UK and U.S. jurisprudence while applying the doctrine.

Test for Doctrine of Equivalents:

Indian courts have applied a three-part functional test similar to UK and U.S. law:

The substitute element performs substantially the same function.

It works in substantially the same way.

It achieves substantially the same result.

2. Key Indian Cases

Case 1: Bayer Corporation v. Union of India & Others (2009)

Facts:

Patent infringement claim related to pharmaceutical compositions.

The alleged infringer produced a formulation slightly different from the claimed composition.

Court Reasoning:

The court recognized that literal interpretation of claims may not be sufficient.

If the substituted ingredient performs substantially the same therapeutic function, it may fall under DoE.

Referred to U.S. and UK cases for the functional approach.

Significance:

First major instance where Indian courts acknowledged Doctrine of Equivalents in pharmaceuticals.

Emphasized function, way, and result as the standard.

Case 2: F. Hoffmann-La Roche Ltd. v. Cipla Ltd. (2008)

Facts:

Roche held patents for HIV drugs; Cipla marketed generic versions.

Patent claims had specific chemical formulations; Cipla made small modifications.

Court Reasoning:

The court examined whether the modifications affected the core inventive principle.

Held that differences that do not substantially alter the working of the invention may still infringe.

Emphasized the purpose of patent protection—preventing circumvention by trivial changes.

Significance:

Indian courts applied DoE cautiously, balancing innovation with generic drug access.

Introduced substantial identity principle.

Case 3: Merck Sharp & Dohme Corporation v. Glenmark Pharmaceuticals Ltd. (2012)

Facts:

Patent on antidiabetic drug formulation.

Glenmark introduced a slightly modified version.

Court Reasoning:

The court adopted a “function-way-result” analysis.

Noted that patent claims should not be narrowly construed to allow easy circumvention.

Even minor chemical substitutions could infringe if overall therapeutic function remains identical.

Significance:

Reinforced DoE applicability in pharma patents.

Highlighted Indian courts’ preference for practical function over literal wording.

Case 4: Novartis AG v. Union of India & Others (2013, SC)

Facts:

The famous “Gleevec” case involved patentability and incremental innovation.

While primary dispute was about Section 3(d), the case also touched upon how modifications of known drugs are assessed.

Court Reasoning:

Observed that inventions must be substantially novel and non-obvious, not minor variations.

While not directly a DoE case, the Supreme Court implied that trivial chemical substitutions that achieve the same result are not inventive, but would constitute infringement under DoE if claimed properly.

Significance:

Informed how courts view small variations under patent law.

Reinforced that DoE applies only if the claimed invention is valid.

Case 5: Roche v. Cipla (2010, Delhi High Court)

Facts:

Roche alleged infringement of its cancer drug patent. Cipla made a similar formulation.

Court Reasoning:

Court explicitly recognized Doctrine of Equivalents, citing UK cases like Catnic Components Ltd. v. Hill & Smith Ltd.

Found infringement under DoE because Cipla’s product:

Performed substantially the same function

In substantially the same way

Achieved substantially the same result

Significance:

Strong affirmation of DoE in Indian context.

Courts emphasize functional similarity over literal claim language.

Case 6: Bayer v. Cipla (2012)

Facts:

Another pharmaceutical patent dispute over cancer drugs.

Cipla introduced minor substitutions to avoid literal infringement.

Court Reasoning:

Applied the “function-way-result” test.

Concluded that slight chemical modifications do not avoid infringement if overall function remains identical.

Court referenced U.S. and UK precedent.

Significance:

Indian courts consistently use DoE in pharmaceutical patent enforcement.

Minor differences are insufficient defense against infringement if core inventive concept is used.

3. Principles Extracted from Indian Cases

Functional Approach: Courts focus on whether the infringing product performs substantially the same function in substantially the same way to achieve the same result.

Doctrine is Not Unlimited:

Cannot cover inventions that are truly new and distinct.

Only applies where differences are trivial substitutions.

Common in Pharmaceuticals:

Most Indian DoE cases involve drug formulations, where slight chemical changes are common.

Reference to Foreign Jurisprudence:

UK: Catnic Components v. Hill & Smith

US: Graver Tank & Mfg. Co. v. Linde Air Products

Validity Requirement:

DoE is applied only to valid patents; an invalid patent cannot be enforced under DoE.

4. Summary Table of Indian DoE Cases

✅ Conclusion

The Doctrine of Equivalents in India:

Protects patentees from circumvention by trivial modifications.

Requires careful functional analysis: same function, same way, same result.

Primarily applied in pharmaceutical patents but can extend to other industries.

Courts refer to UK and US precedents to shape Indian doctrine.