New Delhi: The Delhi High Court has rejected a Japanese firm’s bid to patent a nematode (roundworm)-based cancer detection method, saying it is a diagnostic process barred from patent protection under Indian law, no matter how new or non-invasive the technology might be.
Hirotsu Bio Science moved the high court after India’s Controller of Designs and Patents rejected its application in August 2023, observing that the method did not fulfill the requirements of the Patents Act, 1970.
The 25 page-judgment, delivered by Justice Tejas Karia Saturday reinforces Section 3(i) of India’s Patents Act, which prohibits the patenting of diagnostic methods.
Tiny worms with a sharp nose
The subject of the legal battle was a patent application titled ‘Cancer detection method using (the) sense of smell of nematode’.
Nematodes, commonly known as roundworms, are among Earth’s most abundant organisms, found in diverse habitats from soil to inside other organisms.
The Japanese firm sought to patent a technology centered on the biological behaviour of Caenorhabditis elegans, a type of nematode known for its sophisticated olfactory system.
According to the firm, the invention utilises the chemotaxis of these nematodes: Their movement toward or away from specific scents as a biological indicator for cancer.
The firm claimed these worms exhibit an “avoidance behaviour to the urine of healthy subjects, whereas they have exhibited an attraction behaviour to the urine of cancer patients”. It highlighted the technology’s precision, noting that during testing, “the accuracy was found to be 100%” and was capable of identifying various types of cancers, including gastric, colorectal and pancreatic, even at very early stages.
Is this process patent-able in India?
The core of the dispute centered on whether this method constituted a non-patentable “diagnostic process” under Section 3(i) of the Patents Act, 1970. This section excludes from patentability any process for the medicinal, surgical, curative, prophylactic, diagnostic, or therapeutic treatment of human beings.
Hirotsu Bio Science Inc. appealed against the rejection by India’s Controller of Designs and Patents in the High Court, arguing that their invention was a “detection” method rather than a “diagnostic” one. They contended that the process was an “in vitro method”, conducted entirely in a laboratory environment on samples like urine or tissue, without any physical intervention or medical judgment performed on the human body.
Detection vs diagnosis
The Japanese firm attempted to draw a sharp line between identifying a biological response and making a clinical diagnosis. They argued that their process “does not specify cancer type; it only signals cancer vs non-cancer” and that the term “diagnosis” in their specification was merely illustrative of downstream applications. They further noted that their service, commercialised in Japan as N-NOSE® merely provides information on cancer risk and is not used for definitive medical diagnosis.
The firm relied on the principle that the claims of a patent determine the scope of legal protection, not the description.
However, the Controller of Patents and Designs (the respondents) countered that Section 3(i) makes no distinction between in vivo (inside the body) and in vitro (outside the body) processes. They argued that the claimed method involved all essential steps of diagnosis: “The examination phase involving collection of data, comparison of these data with standard values, the finding of any significant deviation… and the attribution of the deviation to a particular clinical picture”.
Why high court rejected patent
In his analysis, Justice Tejas Karia dismissed the appeal and upheld the patent office’s decision. The court’s reasoning hinged on the interpretation that “Section 3(i) of the Act does not differentiate between the in vivo and in vitro processes”.
Drawing on established jurisprudence, the court noted that if a test is capable of identifying a disease or disorder—even if it is a screening test subject to further confirmation—it qualifies as “diagnostic”. The court found that the firm’s own documentation undermined their argument. The complete specification of the application repeatedly described the invention as a “cancer diagnosis system” capable of detecting early cancer with high accuracy.
The judgment stated: “While there can be no doubt that the subject invention could be a useful invention, the mere fact that it is an in vitro method would by itself be insufficient to make the invention patentable, so long as the purpose of the process is to diagnose a medical condition”.
Court on ‘preparatory steps’
The court also rejected the firm’s attempt to patent secondary claims, such as a method for identifying specific olfactory receptors in nematodes. The court agreed with the patents controller that these were merely “preparatory steps of the claimed diagnostic method” and were of no use when seen in isolation.
Ultimately, Justice Karia concluded that the firm’s attempt to reframe the process as “preliminary screening” in amended claims could not override the technical specifications which showed the method resulted in highly accurate disease identification. By upholding the dismissal, the court has signaled that even highly innovative, non-invasive screening technologies must clear the statutory hurdle of Section 3(i) if their ultimate function is the identification of a pathology.
(Edited by Viny Mishra)
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