A. Introduction

Among the many exclusions to patentability, the Indian Patents Act, 1970 (“the Act”) also excludes “diagnostic methods” under Section 3(i). But the term itself has been applied inconsistently by the Indian Patent Office (“IPO”). This note discusses a recent decision of the Madras High Court on the interpretation of this term and its implications on related patent applications.

B. Background

Section 3(i) of the Act excludes from patentability “any process for the medicinal, surgical, curative, prophylactic diagnostic, therapeutic or other treatment of human beings or any process for a similar treatment of animals to render them free of disease or to increase their economic value or that of their products.”

In the absence of a clear interpretation of the term “diagnostic method” in the Act, this section has been applied inconsistently by the IPO. The issue came up at the Delhi High Court in two separate appeals filed by Sequenom, Inc. and Anr., and EMD Millipore Corporation (MANU/DEOR/158713/2022). In both these cases, the patent applications were refused under section 3(i) for claiming diagnostic methods. Noting that the interpretation of the provision could have a bearing on many patent applications, the Court appointed an Amicus Curiae to assist the Court in these matters, but the cases are still pending.
This note discusses the decision of Madras High Court in Chinese University of Hong Kong and Sequenom, Inc. v. The Assistant Controller of Patents and Designs, CMA (PT) No.14 of 2023. Here, the matter was brought to the High Court after the Controller had refused the patent application (4812/CHENP/2012) titled “Fetal Genomic Analysis from a Maternal Biological Sample” on the ground that its claims fell under Section 3(i) for being directed to a diagnostic method.

C. Two limbs of Section 3(i)

The Court held that Section 3(i) has two limbs:

1. any process for the medicinal, surgical, curative, prophylactic diagnostic, therapeutic or other treatment of human beings; or

2. any process for a similar treatment of animals to render them free of disease or to increase their economic value or that of their products.

The Court said that these limbs are distinct and self-contained for three reasons:

1. the first limb deals with human beings and the second with animals;

2. the disjunctive ‘or' separates the two limbs.

3. the second limb opens with the expression “any process for a similar treatment of animals” and sets out three purposes of treatment, of which, the latter two are clearly inappropriate and inapplicable to human beings.

D. “diagnostic” is not confined to “rendering free from disease”

The Court noted that treatment is provided not only to cure disease but also for prophylactic purposes, to alleviate pain, prevent aggravation of, or better manage, a condition or disorder. Therefore, the word “diagnostic” should not be confined to treatment of human beings to render them free from disease.
The Court said that Section 3(i) is essentially a sandwich phrase, “any process for the… treatment of human beings”, with the sentence to be completed by one of the terms listed: medicinal, surgical, curative, prophylactic, diagnostic and therapeutic. The Court held that the construction works perfectly with all the terms except “diagnostic”.

The terms – medicinal, surgical, curative, prophylactic and therapeutic – clearly indicate methods of treatment of human beings. However, the phrase “or other treatment” also indicates that the word “treatment” is intended to be construed widely.

The Court noted that “diagnostic method” is essentially a method of identifying the existence or non-existence of a disease or condition and/or the site, extent, severity or other aspects thereof. Mere identification is not a form of treatment. Consequently, the expression “any process for the diagnostic treatment of human beings” makes little sense, unlike with the forms of treatment mentioned in Section 3(i).

Diagnosis is a prerequisite for treatment, and the two are distinct processes. Because the word “diagnostic” in Section 3(i) is alongside words like “medicinal” or “surgical”, that are forms of treatment, “diagnostic” should not be construed in isolation but should be understood in association with the accompanying words.

Thus, when viewed in context, the Court concluded that the word “diagnostic” should be limited to diagnostic processes that disclose pathology for the treatment of human beings.

The Court stated claims in a patent application, therefore, should be examined in the context of the complete specification, to determine whether it specifies a process for making a diagnosis for treatment. If it is concluded that a diagnosis for treatment may be made, even if such diagnosis is not definitive, it would be patent ineligible, whereas, if diagnosis for treatment cannot be made, it would be patent eligible.

E. “diagnostic” not confined to in vivo diagnosis

The Court also rejected the contention that diagnostic processes should be confined to in vivo diagnosis, and pointed to the legislative history of Section 3 as well its ‘parent' Article 27(3)(a) of the Agreement on Trade-Related Aspects of Intellectual Property Rights (TRIPS) to support this position.

Article 27(3)(a) enables members to exclude from patent eligibility the following: ‘diagnostic, therapeutic and surgical methods for the treatment of humans or animals' (emphasis added), but there is no other limitation or restriction in the scope of “diagnostic methods”.

F. Methods of Screening

The Court said that if a screening test is capable of identifying the existence or otherwise of a disease, disorder or condition and/or the site, extent, severity or other aspects, for treatment of human beings, irrespective of whether or not the person is symptomatic, such screening test would qualify as a diagnostic test. In other words, the label used for the test – be it screening or anything else – is not determinative.

The Court said that whether a test is diagnostic or not depends on whether the test is inherently and per se capable of identifying the disease, disorder or condition for treatment of the person. If the person(s) skilled in the art is unable to diagnose thus on the basis of the process, because the process is not designed to diagnose, whether labelled as screening or anything else, it would not qualify as diagnostic for purposes of Section 3(i).

G. Present Case

The patent application under examination contained claims directed to a method of determining a fractional concentration of fetal DNA in a biological sample taken from a pregnant female. The claimed invention is per se incapable of identifying the existence or otherwise of a disease, disorder or condition and further testing would be required for such purpose. The determination of foetal fraction is related to diagnosis but is not “diagnostic”. Hence, the Controller's objection under Section 3(i) was rejected.

H. Other Observations

The Court also took note of inconsistencies in the IPO's determinations, including with regard to the grant of patents to in vitro processes. The Court said that several technological advancements have been made in diagnosis, especially with reference to genomic tools. In order to incentivise inventors, without compromising on the exclusion from patent eligibility, there is a case to consider options such as restricting the scope of the expression ‘diagnostic' in Section 3(i) to in vivo processes and counter-balancing by providing for compulsory licensing.

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