Summary
The Delhi High Court affirmed the Patent Office’s refusal of Sequenom’s NIPT claims, holding them barred as diagnostic methods under Section 3(i). Reading 3(i) purposively, the Court said in vitro processes that effectively confirm or rule out abnormalities are diagnostic, even if styled as screening, and noted that sex determination aspects invite Section 3(b) objections. Devices and tools remain eligible if they satisfy patentability, but diagnostic processes do not.
The Delhi High Court upheld the Patent Office’s refusal of Sequenom’s patent applications for non-invasive prenatal testing (NIPT), ruling them non-patentable under Section 3(i) of the Patents Act, 1970. The Court found that although Sequenom’s method was framed as a screening test, it effectively performed a diagnostic function by accurately identifying or ruling out chromosomal abnormalities, thus falling within the exclusion for diagnostic methods. The Court clarified that while methods of diagnosis are excluded, diagnostic tools and products may still be eligible for patent protection under Section 3(i).
Background
Sequenom Inc. and Sequenom Center for Molecular Medicine (hereinafter “Sequenom”) filed two Indian patent applications, No. 2476/DELNP/2011 and No. 3139/DELNP/2012, titled “Process and Compositions for Methylation-Based Enrichment of Fetal Nucleic Acid from a Maternal Sample Useful for Non-Invasive Prenatal Diagnoses” (hereinafter “the subject inventions”). The claims in both applications were largely identical, differing only in the specific polynucleotide sequence identifiers.
The invention related to an in vitro method for detecting fetal chromosomal abnormalities (aneuploidy) by selectively digesting maternal DNA using methylation-sensitive enzymes to enrich fetal DNA from a maternal sample, followed by amplification, sequencing, and comparison of target and reference chromosome regions to identify abnormalities. The method enabled identification of pregnancies at high risk of chromosomal abnormalities or genetic conditions, allowing informed decision-making.
The first application was refused by the Assistant Controller of Patents (hereinafter “Controller”) on the grounds of lack of inventive step under Section 2(1)(ja) and non-patentability under Sections 3(b), 3(d), 3(i), and 3(j) of the Patents Act, 1970 (“the Act”). Sequenom filed an appeal before the Intellectual Property Appellate Board (IPAB), which was later transferred to the Delhi High Court following the Tribunal Reforms (Rationalization and Conditions of Service) Ordinance, 2021. The second application was similarly refused under Section 3(i).
Given the common issue of the scope and interpretation of Section 3(i), the appeals were tagged together and heard alongside a batch of appeals presenting similar questions regarding the exclusion of diagnostic methods under Section 3(i). The Court appointed Mr. Adarsh Ramanujan as Amicus Curiae to assist in interpreting Section 3(i).
Arguments by Parties
Sequenom argued that the subject inventions were Non-Invasive Pre-Natal Screening (NIPS) Tests, not diagnostic tests, as they only indicated the risk of chromosomal abnormalities and required subsequent confirmatory tests for a definitive diagnosis. They pointed out that NIPS tests are probabilistic and may produce false positives, unlike diagnostic tests, which are conclusive. Sequenom relied on medical literature, WHO guidelines, and global policy statements to establish that NIPTs are non-diagnostic and only serve as preliminary risk indicators. They further contended that patent law must evolve alongside technological advancements, and excluding an entire area of innovation would discourage innovators. They also relied on the Madras High Court’s ruling in Chinese University of Hong Kong v. Assistant Controller of Patents (2023), which held that only methods capable per se of uncovering pathology qualify as diagnostic under Section 3(i).
The Controller’s counsel argued that diagnostic processes, including preliminary screening, involve interlinked steps that cannot be separated into distinct “screening” and “analysis” stages. They further contended that Sequenom’s test, which determines fetal aneuploidy, sex, and chromosomal abnormalities with over 99% accuracy, functions as a diagnostic tool capable of effectively substituting for amniocentesis, making it a non-patentable diagnostic method.
Mr. Adarsh Ramanujan, the Amicus Curiae, submitted that Section 3(i) should be interpreted narrowly, applying only to diagnostic processes that independently lead to curative treatment, and not to intermediate or screening methods. He stressed the importance of claim construction, economic implications, and innovation, noting that overly broad interpretations of Section 3(i) would unduly stifle innovation in biotechnology and medical research, contrary to the purpose of patent law.
Issues before the Court
(I) What is the scope of exclusions from patentability under Section 3(i) in respect of diagnostic methods?
(II) Whether the subject invention is excluded from patentability under Section 3(i)?
Court’s Observations
Issue I: Scope of exclusions from patentability under Section 3(i)
The Court observed that Section 3(i) of the Patents Act, originally framed when a “method of manufacture” was a prerequisite for patentability, must now be interpreted in light of the modern definition of “invention,” which includes both products and processes that are novel, inventive, and industrially applicable. It held that the exclusion under Section 3(i) is intended to safeguard the autonomy of the medical profession and ensure unhindered access to essential medical procedures, not to impose a blanket bar on all medical innovations. Only methods that directly involve professional medical judgment or invasive, high-risk procedures are excluded from patentability, while tools, devices, and non-invasive or in vitro methods remain patentable if they meet statutory requirements.
The Court clarified that the exclusion applies only to interventions on living humans or animals and does not extend to technologies, including AI-assisted diagnostic tools, that aid but do not replace medical professionals’ judgment. It emphasised that Section 3(i) must be interpreted narrowly and purposively to balance medical freedom with technological innovation. The Court suggested that the Legislature may need to clarify the wording of Section 3(i) to remove ambiguity and ensure consistency with international standards.
Issue II: Whether the Subject Invention is Excluded from Patentability under Section 3(i)
The Court observed that although Sequenom’s invention was conducted in vitro, the purpose and effect of the process was to diagnose or rule out fetal abnormalities. The high sensitivity (98.6%) and specificity (99.8%) of the test meant that its results effectively determined whether further medical intervention (such as confirmatory invasive testing) was necessary.
The Court clarified that Section 3(i) encompasses both positive and negative diagnoses, that is, methods that either detect the presence of a disease or eliminate the possibility of it. Allowing patents on tests that eliminate patients from diagnostic pathways would, in the Court’s view, undermine the legislative intent of the exclusion.
Consequently, the Court held that the claimed inventions were diagnostic methods within the meaning of Section 3(i) and therefore excluded from patentability, notwithstanding that they were performed outside the human body. Further, since one embodiment involved determining fetal sex through the presence of the Y chromosome, the invention also contravened Section 3A of the Pre-Conception and Pre-Natal Diagnostic Techniques (Prohibition of Sex Selection) Act, 1994, and was consequently hit by Section 3(b) of the Patents Act on grounds of public morality.
Conclusion
The Court dismissed the appeals, upholding the Patent Office’s refusal of grant and affirming that the claimed methods were non-patentable under Sections 3(i) and 3(b) of the Act. It reiterated that while devices, tools, and products are not excluded under Section 3(i), methods and processes used for diagnosis, even when conducted in vitro, are excluded.
Citation
Sequenom Inc & Anr vs The Controller Of Patents on 9 October, 2025. Available at https://indiankanoon.org/doc/19170869/
Article Review: Dr. Vasundhara Paliwal
Accessibility Review: Rakesh Krishnan
Relevant Extracts
- Thus, in view of the above discussion, the salient points for interpretation of Section 3(i) of the Act may be summarised as under:
(i) Products used for diagnosis or therapeutic purposes, including kits, equipment, machines, and physical products, which satisfy the conditions of patentability do not fall within the scope of exclusions under Section 3(i) of the Act and would hence be patentable.
(ii) A perusal of the various terminologies used in Section 3(i) of the Act shows that the exclusions are meant for processes which are employed by medical practitioners, para-medical personnel, nurses, etc. The interpretation of key terms in Section 3(i) of the Act in the context of other provisions of the Act would be as under:
(a) ‘Medicinal process’ would mean processes which are used for administration of medicines such as a process for oral administration, a process for administration through intravenous therapy, a process for administration of medicine through topical, transdermal or subcutaneous routes or a process through insertion of the medicine, etc. but would not include medicinal products, medicines, medical devices, or even patentable product by process inventions.
(b) ‘Surgical process’ means a process of performing surgery.
However, surgical tools, surgical implements including surgical methods using novel tools and implements would all be patentable. For example, the manner of conducting a colonoscopy or heart transplant surgeries, including the method for sutures or the manner of creating an incision, etc., which are commonly used by surgeons would not be patentable. However, a novel product such as an innovative scalpel used in conducting the surgery would be patentable.
(c) ‘Curative process’ – this terminology is quite ambiguous and vague, considering the various other terms and expressions used in Section 3(i) of the Act. Curative means “treatments and therapies aimed at eliminating a disease, injury, or illness to restore a person’s health to its prior state”. Thus, a process adopted by a medical practitioner for curing or healing a disease would not be patentable, but tools and products or novel patentable methods used for the same would not be excluded.
(d) ‘Prophylactic process’ means a process for prevention of disease, for example, a process of administering a vaccine or a process of conducting cancer screening, blood test etc., would not be patentable. However, preventive tools, preventive products or preventive mechanisms which qualify the test of patentability would not be excluded.
(e) ‘Diagnostic process’ – The manner in which diagnosis is performed would not be patentable, for example, the manner of checking blood pressure using different tools, the manner of doing a swab test, the process of checking glucose levels, etc., would not be patentable. However, diagnostic products, diagnostic tools, diagnostic devices are patentable so long as they satisfy the test of patentability and they do not unfairly monopolize processes of diagnosis which are to be generally used by medical practitioners, nurses etc. It is also clear that Section 3(i) does not make any distinction between in vivo or in vitro processes.
(iii)Tools which could be used for the purpose of diagnosis would also not be covered by the exclusion and would be patentable. However, if tools only consist of software-based tools, which utilize data for the purpose of diagnosis, they would have to be examined under Section 3(k) of the Act for further technical effect and for satisfying the conditions for patentability. In addition, it would have to be checked if these tools or processes by themselves give results which are capable of clear interpretation as to the existence or non-existence of a medical condition.
(iv)The phrase “to render them free of disease or to increase their economic value” qualifies only treatment of animals and not of human beings;
(v) Mere identification of the regimen for the use of certain medicines in a particular manner or frequency or form would be excluded from patentability.
(vi)Methods of treatment of plants are not covered by Section 3(i) of the Act and would be patentable so long as the test of Section 3(j) of the Act is satisfied.
- The interpretation of Section 3(i) of the Act or equivalent provisions in foreign jurisdictions has been a challenge for Courts and Tribunals which are attempting to strike a balance between protecting genuine innovations on the one hand and ensuring that grant of patents does not impede medical practitioners and those working in the field of medicine from using day to day processes, which are required to be employed in the field of medicine for human beings or even for animals. There may be a need for taking a re-look at the wording of this provision in order to remove ambiguity and vagueness and provide further clarity, consistency and predictability in patenting. This would, however, be in the realm of policy and the Legislature. Issue II: Whether the subject invention is excluded from patentability under Section 3(i) of the Act?
