Japanese Company Fails to Secure Indian Patent for Cancer Detection Using Nematodes

New Delhi: In a significant ruling interpreting the scope of patent exclusion for diagnostic methods in India, the Delhi High Court has dismissed an appeal filed by Hirotsu Bio Science Inc., thereby upholding the rejection of its patent application for a cancer detection method using the sense of smell of nematodes.

The Court ruled that the claimed invention falls squarely within the prohibition under Section 3(i) of the Patents Act, 1970, which excludes diagnostic methods from patentability.

The appeal challenged an order of the Assistant Controller of Patents and Designs rejecting the application on the ground that it constituted a diagnostic process, notwithstanding the applicant’s assertion that it was merely an in vitro detection method.

Hirotsu Bio Science Inc. filed a national phase patent application on 4 July 2016, based on an international PCT application titled “Cancer Detection Method Using Sense of Smell of Nematode.” The invention relied on the chemotaxis (olfactory response) of the nematode Caenorhabditis elegans to detect cancer-specific odours in biological samples such as urine.

After issuance of the First Examination Report (FER) raising objections under Sections 2(1)(j), 3(i), 3(j) and Section 10(4) of the Act, the applicant submitted responses and amended claims. A hearing was conducted in April 2023, followed by written submissions.

However, by order dated 29 August 2023, the Assistant Controller rejected the application under Section 15, holding that the invention amounted to a diagnostic method barred under Section 3(i). Aggrieved, the applicant approached the Delhi High Court under Section 117A of the Act.

The petitioner contended that its invention was not diagnostic, but merely a detection method carried out in vitro, entirely outside the human body. It argued that diagnosis necessarily requires medical interpretation and clinical judgment, whereas the claimed invention only provided a preliminary indication of cancer risk.

The petitioner emphasized that the claims, not the specification, define the scope of protection. According to it, the specification merely provided contextual background and illustrative downstream uses, while the claims were strictly limited to laboratory-based detection.

Strong reliance was placed on judicial precedents such as EMD Millipore Corporation v. Assistant Controller of Patents and Chinese University of Hong Kong v. Assistant Controller of Patents, to argue that not all detection or screening methods qualify as diagnostic under Section 3(i).

The petitioner also highlighted that its technology has been commercially deployed in Japan under the brand “N-NOSE®”, functioning as a risk-indication tool rather than a diagnostic test, thereby reinforcing its argument that the invention does not culminate in diagnosis.

The Patent Office strongly opposed the appeal, asserting that Section 3(i) excludes both in vivo and in vitro diagnostic methods, and the statute makes no distinction between the two. It argued that permitting patentability merely by labeling a method as “in vitro” would defeat the legislative intent.

The respondent submitted that the claimed invention satisfied all essential steps of a diagnostic process—data collection, comparison with standards, detection of deviation, and attribution to a disease condition. It relied on Supreme Court and High Court precedents to argue that even screening tests qualify as diagnostic if they identify disease presence, even subject to confirmation.

The respondent further argued that the complete specification repeatedly described the invention as a “cancer diagnosis system”, capable of detecting early-stage cancer with high sensitivity and specificity, making it inherently diagnostic in nature.

After an extensive analysis of statutory provisions, claims, and the complete specification, the Court rejected the petitioner’s distinction between detection and diagnosis.

The Court observed:

“Section 3(i) of the Act does not differentiate between the in vivo and in vitro processes.”

Rejecting the argument that medical expertise is required for a process to qualify as diagnostic, the Court held:

“It is immaterial who performs the method. In such a situation, it would be challenging if this section is kept limited to only methods practiced by medical practitioners.”

On the nature of the invention, the Court noted:

“Based on the discussion of the Complete Specification, it is inferred that the Complete Specification of the Subject Application provide that the process sought to be patented is not limited to just a screening process… but it also is a general diagnosing method for cancer.”

The Court further emphasized that claims cannot be read in isolation:

“Even assuming that the amended claims claim only screening, the claims cannot be read contrary to specifications.”

Finally, the court stated,

“The Impugned Order rightly noted the steps involved in the Subject Application while providing reasons for the claimed method to be a diagnostic method. Accordingly, the Appeal is dismissed and the Impugned Order dated 29.08.2023 is upheld.”

“The proposed claims cannot be allowed under Section 3(i) of the Act.”

“Accordingly, the Appeal is dismissed.”

To view the official order, click the link below: