Doctrine of equivalents in biotech patents

Introduction

The Doctrine of Equivalents is a principle of patent law used to determine whether a product or process infringes a patent even when it does not fall within the exact wording of the patent claims. Under this doctrine, a person may be held liable for infringement if the allegedly infringing invention performs substantially the same function, in substantially the same way, to achieve substantially the same result as the patented invention.

In biotechnology, this doctrine is particularly important because small changes in DNA sequences, proteins, microorganisms, biological processes or genetic engineering techniques may produce inventions with similar functions. The doctrine seeks to prevent competitors from avoiding patent protection merely by making insignificant technical modifications. However, it must be balanced against the public interest in keeping scientific discoveries and unpatentable subject matter available for research.

Legal framework in India

The Indian Patents Act, 1970 does not expressly define or establish the Doctrine of Equivalents. Patent infringement is primarily assessed under Section 48, which grants patentees exclusive rights over the patented product or process, subject to the scope of the claims.

The scope of protection is determined mainly by the patent claims, read with the complete specification. Section 10 requires the specification to describe the invention and clearly define the claims. Section 3 also excludes certain subject matter from patentability, including discoveries of living things and naturally occurring substances, as well as plants and animals in whole or in part, subject to the statutory exceptions.

In biotechnology, these provisions are relevant to patents involving recombinant proteins, vaccines, engineered microorganisms, diagnostic methods and genetic technologies. The doctrine cannot be used to extend a patent beyond its legally permissible subject matter.

Application in biotechnology patents

The doctrine may become relevant when a competitor changes a technical feature without substantially changing the invention's essential operation. For example, a patented process may use a particular enzyme to produce a biological compound. A competing process may use a slightly modified enzyme that performs substantially the same function through a materially similar mechanism. Whether infringement exists would depend on the patent claims, technical evidence and applicable legal principles.

Courts may consider:

Function: Whether the allegedly infringing feature performs substantially the same function.

Way: Whether it operates through substantially the same technical mechanism.

Result: Whether it produces substantially the same outcome.

Materiality of change: Whether the modification represents a genuine technical difference or merely an insignificant substitution.

In biotechnology, however, even small molecular changes may substantially alter biological activity, safety, stability or therapeutic effect. Therefore, similarity of results alone is insufficient to establish infringement.

Important case laws

1. Raj Prakash v. Mangat Ram Chowdhry (1978)

The Delhi High Court examined patent infringement and emphasised that a defendant cannot avoid infringement merely by making colourable or insignificant variations to a patented invention. The judgment supports a substance-over-form approach when examining technical similarities. Its reasoning may be relevant by analogy to biotechnology patents, although it did not specifically concern biological inventions.

2. Bishwanath Prasad Radhey Shyam v. Hindustan Metal Industries (1979)

The Supreme Court discussed patent validity, inventive step and the distinction between a genuine invention and an obvious modification. Although the case was not directly about the Doctrine of Equivalents, it is relevant because courts must distinguish a substantial technical advance from an insignificant alteration when examining patent disputes.

3. F. Hoffmann-La Roche Ltd. v. Cipla Ltd. (2008)

The Delhi High Court considered a dispute concerning the cancer medicine Erlotinib. The case involved patent infringement, claim interpretation and the relationship between patent protection and public interest. It illustrates the importance of examining the actual patent claims and technical characteristics rather than relying only on broad similarities between products.

4. Novartis AG v. Union of India (2013)

The Supreme Court considered the patentability of the beta-crystalline form of Imatinib Mesylate under Section 3(d) of the Patents Act. The Court emphasised the need to satisfy statutory patentability requirements and demonstrate enhanced therapeutic efficacy for qualifying new forms of known substances. Although not an infringement case, it establishes an important limitation: the Doctrine of Equivalents cannot be used to bypass statutory restrictions on patentability.

Challenges in biotechnology

Applying the doctrine to biotechnology creates several difficulties. Biological systems are complex, and minor molecular changes can produce significantly different effects. Determining whether two proteins, genetic sequences or microorganisms are equivalent may require expert scientific evidence and laboratory analysis.

Another challenge concerns research freedom. If the doctrine is interpreted too broadly, it may discourage follow-on research, development of improved medicines and innovation in agricultural biotechnology. It may also create uncertainty for generic manufacturers and research institutions.

Indian courts must therefore balance patent-holder rights with public health, scientific progress and the statutory exclusions under the Patents Act.

Conclusion

The Doctrine of Equivalents can help prevent the misuse of minor technical modifications to avoid patent infringement in biotechnology. However, Indian patent law does not expressly codify this doctrine, and infringement must principally be determined through the patent claims and applicable statutory provisions. Courts should carefully examine technical function, mechanism and result while respecting patentability restrictions and public interest. A balanced approach can protect genuine biotechnology inventions without unnecessarily restricting scientific research and access to essential medicines.