Case Title: Natera Inc and Anr. Vs Assistant Controller of Patents and Designs
Order Date: 9th October 2025
Case Number: C.A.COMM.IPD-PAT 162023
Neutral Citation: 2025:DHC:162023
Court: High Court of Delhi at New Delhi
Hon'ble Judge: Justice Prathiba M. Singh
Fact:
Natera Inc, a California-based company specializing in clinical genetics including cell-free DNA testing technology, along with UCL Business Ltd., filed an Indian patent application on 5th September 2019 titled "Methods for Lung Cancer Detection." The invention concerns a laboratory method to detect and monitor genetic mutations associated with lung cancer, specifically lung squamous cell carcinoma (a type of non-small cell lung cancer), by amplifying and sequencing tumor-derived DNA from blood samples. The method involves performing multiplex PCR amplification on nucleic acids isolated from blood or its fractions, followed by the analysis of single nucleotide variants (SNVs) associated with lung cancer. The technology is characterized by high sensitivity and the ability to detect mutations relevant for diagnosis, staging, and monitoring. The appellants claimed priority from a U.S. application dated 15th April 2016 and filed multiple amended claims through prosecution to refine the scope.
Procedural Details:
The Indian Patent Office issued a First Examination Report (FER) dated 31st August 2021 raising objections including lack of novelty and inventive step under Sections 21(j) and 21(ja), non-patentability under Sections 3(d) (improvement) and 3(i) (diagnostic exclusion), and non-compliance with formalities under Sections 104(c) and related procedural rules. The appellants responded with amended claims, reduced from 54 to 15 and finally to 8 claims. A hearing was conducted on 9th January 2023, but the application was refused by the Assistant Controller of Patents via order dated 20th March 2023 primarily on the ground that Claims 1 to 4 were excluded from patentability under Section 3(i) of the Patents Act, as the method was diagnostic for lung cancer detection. Claims 5 to 8 were held impermissible by Section 59 because they were considered beyond the scope of the original specification. The appellants challenged this refusal before the Delhi High Court under Section 117A of the Patents Act.
Dispute:
At the core lies the interpretation of Section 3(i), which excludes from patentability methods for diagnosis practiced on humans or animals. The appellant argued that the invention was a laboratory, in vitro process for detecting the presence of specific genetic variants associated with lung squamous cell carcinoma and did not itself constitute a diagnostic method practiced on the human body. They contended the claims were related to research, predisposition testing, and monitoring, not treatment or diagnosis requiring professional judgment. The respondent (Patent Office) insisted that since the complete specification described the method as improving detection, diagnosis, staging, screening, and treatment of lung cancer, the claims fell squarely within the non-patentable subject matter under Section 3(i). Further, the respondent maintained claims 5-8 were impermissible amendments beyond the original scope, violating Section 59.
Detailed Reasoning:
The Court carefully examined the language of Section 3(i) of the Patents Act, 1970, which 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..." The Court reviewed similar provisions in foreign jurisdictions, notably the UK Patents Act 1977 and Article 53(c) of the European Patent Convention (EPC), which excludes methods of diagnosis practiced on the human or animal body but allows patents on substances or compositions used in those methods.
The Court referenced the landmark Enlarged Board of Appeal decisions of the European Patent Office defining diagnostic methods as multi-step processes practiced on the body, including: collecting data, comparing this with standard values, identifying deviations, and reaching a diagnostic decision. The exclusion applies narrowly to core medical activities that require professional skill and pose health risks, ensuring medical practitioners can diagnose and treat without infringing patents.
The subject matter of the invention was found to be an in vitro laboratory technique that amplifies and sequences nucleic acids from blood samples without direct diagnostic acts on the human body. The Court observed that the method provides genetic data related to tumor mutations but does not itself perform diagnosis, treatment, or clinical decision-making. The Court also noted that distinguishing between in vivo (on the body) and in vitro (outside the body) diagnostic methods is key: Section 3(i) does not distinguish them explicitly but the context and judicial interpretation limit exclusion to processes practiced on living bodies.
The Court further examined the detailed claims and specification, finding them aimed at detecting the presence of lung squamous cell carcinoma-associated single nucleotide variants in blood samples. The invention facilitates early detection, monitoring, and research but does not make a medical diagnosis or prescribe treatment. Hence, the Court held the process qualifies for patentability under Indian law as it falls outside the exclusion of Section 3(i).
On the question of claims 5 to 8, the Court considered Section 59 of the Act restricting amendment beyond disclaimers, corrections, or explanations. The appellants argued these claims were supported by earlier PCT claims and thus should be allowable without extending original scope. The Court referenced precedents including Axcess Limited v Controller of Patents (2024) and Allergan Inc. v Controller of Patents (2023) which endorse allowance of amendments within the scope of the original application. The Court found that these claims were within the ambit of the original specification and supported by original filings, therefore rejecting the Patent Office's objection under Section 59.
The Court also reviewed the inventive step objections but clarified that these were not examined in the impugned order and were to be decided separately.
In conclusion, the Court adopted a balanced interpretation of Section 3(i), ensuring the protection of genuine medical diagnostic processes practiced on living beings from patent monopolies to safeguard public health, while protecting innovative technical methods and tools used in diagnostics outside the human body.
Decision:
The appeal was allowed. The impugned order refusing the patent application was set aside. The Court held that Claims 1 to 4 do not fall under the non-patentable exclusions of Section 3(i) as the invention constitutes an in vitro laboratory method and not a diagnostic method practiced on the human body. Claims 5 to 8 were also held to be permissible amendments under Section 59 of the Act as they did not extend beyond the original scope. The Patent Office was directed to grant the patent after completion of formalities. The Court emphasized that the ruling strikes a balance between public interest and incentive for innovation and clarified interpretation principles for Section 3(i) exclusions to aid consistent patent examination in future.
Relevant Legal Provisions Discussed:
Section 3(i) of the Patents Act 1970 (Exclusion of diagnostic, therapeutic, surgical processes)
Section 21(j) and 21(ja) (Novelty and Inventive step)
Section 59 of the Patents Act 1970 (Amendments to patent applications)
Section 117A (Appeals from Controller's decisions)
Article 53(c), European Patent Convention (EPC 2000)
Section 4A, UK Patents Act 1977
Enlarged Board of Appeal decisions G 000104 and G 000107 of the European Patent Office
Relevant Indian case precedents: Axcess Limited v Controller, Allergan Inc. v Controller, Novartis AG v Union of India (2013)
Disclaimer: The information shared here is intended to serve the public interest by offering insights and perspectives. However, readers are advised to exercise their own discretion when interpreting and applying this information. The content herein is subjective and may contain errors in perception, interpretation, and presentation.
Written By: Advocate Ajay Amitabh Suman, IP Adjutor [Patent and Trademark Attorney], High Court of Delhi
Suggested Titles for Legal Research Paper:
"Interpretation of Section 3(i) of the Indian Patents Act: Diagnostic Methods and Patentability in Natera Case"
"Balancing Innovation and Public Health: Legal Analysis of Patent Exclusions for Diagnostic Processes"
"Patent Law and Diagnostic Inventions in India: Insights from Natera Inc. v. Assistant Controller"
"Scope and Limits of Non-Patentable Subject Matter: Detailed Study of Diagnostic Method Exclusions"
"Amendments and Patentability: Legal Challenges in Diagnostic Method Patents under Indian Law"
