Summary
The Delhi High Court in Hirotsu Bio Science v. Assistant Controller of Patents and Designs upheld rejection of a nematode-based cancer detection application as a diagnostic method hit by Section 3(i). Reading the claims with the specification, the Court held that in vitro screening capable of identifying cancer, even at an early stage, is per se diagnostic. It further clarified that the bar under Section 3(i) does not depend on whether the method is performed in vivo or in vitro, or by a doctor or a machine.
The Delhi High Court, in Hirotsu Bio Science Inc. v. Assistant Controller of Patents and Designs, upheld the Patent Office’s refusal of Patent Application No. 201617022947 relating to a cancer detection method based on the olfactory response of nematodes. The Court found that the claimed invention fell within the exclusion under Section 3(i) of the Patents Act, 1970, as it constituted a diagnostic process. The Court clarified that merely characterising the claims as relating to “in vitro detection” does not place the invention outside the statutory bar, since the specification and claims, read as a whole, are directed to diagnosing cancer.
Background
Hirotsu filed a PCT national phase application titled “Cancer Detection Method Using Sense of Smell of Nematode.” The application claimed in vitro methods for detecting cancer and identifying cancer types by observing the behavioural (olfactory) response of the nematode Caenorhabditis elegans to biological samples, particularly urine. The specification disclosed that nematodes are repelled by urine from healthy individuals and attracted to urine from cancer patients, with experimental results indicating high accuracy, including in early-stage cancers.
The Assistant Controller of Patents and Designs (“Controller”) rejected the application under Section 3(i) of the Patents Act. Hirotsu appealed this decision before the Delhi High Court, contending that the invention concerned mere “detection” rather than “diagnosis,” and therefore fell outside the scope of Section 3(i).
Arguments by Parties
Hirotsu argued that the core inventive feature lay in an in vitro detection process that only indicates the possibility of cancer and does not amount to diagnosis. Although the specification discusses both detection and diagnostic contexts, the claims, according to Hirotsu, are strictly confined to in vitro detection, with no step performed on a human or animal body. It was submitted that that references to “diagnosis” in the specification are illustrative of potential downstream applications and not part of the claimed invention. Hirotsu further pointed to the commercialised “N-NOSE®” service in Japan, which signals cancer risk without providing a definitive diagnosis, as evidence that the invention functions merely as a detection or screening tool.
The Controller contended that Section 3(i) does not distinguish between in vivo and in vitro methods, and that any process aimed at diagnosing a disease is excluded from patentability. The Controller argued that, when read in light of the specification, the method is directed to identifying cancer, and its functional outcome qualifies it as a diagnostic process. It was further submitted that the method incorporates all essential steps of diagnosis namely, data collection, comparison with standards, identification of deviations, and attribution to a clinical condition. The Controller reiterated that Claim 5, relating to identification of nematode olfactory receptors, was integral to determining cancer type.
Key Issue
Whether the claimed “in vitro detection” method falls within the exclusion of a diagnostic process under Section 3(i) of the Patents Act.
Court’s Analysis and Findings
The Court observed that Section 3(i) draws no distinction between in vivo and in vitro diagnostic methods, and that claims must be construed in conjunction with the specification, not in isolation. The Court reiterated that even in vitro screening tests capable of identifying disease conditions qualify as diagnostic methods excluded under Section 3(i). Although Hirotsu characterised the invention as mere detection, the Court noted that the specification repeatedly asserts accurate cancer identification, including at early stages, and discloses steps analogous to diagnosis, namely data collection, comparison with reference values, and attribution to a disease condition.
Relying on Chinese University of Hong Kong decision, the Court underscored that that if a skilled person can arrive at a diagnosis from the disclosed process, the method is per se diagnostic and patent-ineligible, even if the diagnosis is not definitive or comprehensive.
The Court further clarified that the identity of the person performing the method is immaterial. Restricting Section 3(i) solely to procedures carried out by medical practitioners, according to the Court, would permit patenting of fully autonomous diagnostic processes, defeating the legislative intent of the exclusion.
Conclusion
The Court concluded that the claimed invention, in substance, constitutes a general method for diagnosing cancer. Accordingly, it upheld the Controller’s rejection of the application and dismissed the appeal.
Citation
Hirotsu Bio Science Inc vs Assistant Controller Of Patents And Designs, Delhi HC, 17 January, 2026, C.A.(COMM.IPD-PAT) 45/2023.
Available at https://indiankanoon.org/doc/164201917/
Article Review: Dr. Vasundhara Paliwal