Every so often, a court decision quietly redraws the boundaries of an entire discipline. The Delhi High Court's decision by Justice Manmeet Pritam Singh Arora in Geron Corporation v. Assistant Controller of Patents and Designs¹ is one such ruling for Indian patent law and practice.

Section 3(i) of the Indian Patents Act, 1970, which aims to prevent monopolies over medical practices, has long been a puzzle for innovators in the field of biotechnology and related disciplines. In the last few years, the Delhi and Madras High Courts have delivered a series of path-breaking judgments interpreting this provision in the context of cutting-edge biotechnology and related inventions.

In the Geron case, Justice Manmeet Pritam Singh Arora delivered a clear decision that claim language cannot override the function of the invention. Such cases illustrate how Indian courts have moved from a narrow "in-vivo-only" reading to a functional test.

Geron Corporation (Appellant), a U.S.-based large-stage clinical biopharmaceutical company, filed Indian Patent Application No. 4506/DELNP/2015, claiming an in vitro screening method that measures telomere length in cancer cells to identify patients who might respond to telomerase inhibitor therapy. If the telomere length falls at or below the 50^th percentile of a known standard, the individual is selected for telomerase inhibitor treatment.

However, the Controller of Patents rejected the patent application as non-patentable under Section 3(i) of the Patents Act, characterising it as a diagnostic method rather than a screening method.

Geron Corporation filed an appeal under Section 117-A of the Indian Patents Act, 1970 and argued that the claimed invention is merely a screening tool applied after diagnosis — not a diagnostic method — since the patient is already diagnosed with cancer and the method only helps decide treatment eligibility.

The Court upheld the Controller's decision of refusal of the Patent Application.

As per Section 3(i) of the Indian Patents Act, "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 to render them free of disease or to increase their economic value or that of their products" does not constitute an invention.

Further, diagnostic methods are specifically excluded from patentability as per the Guidelines for Examination of Biotechnology Applications for Patent issued by the office of the Controller General of Patents, Designs and Trademarks.

The Guidelines indicate that biomarker-based monitoring of drug response in a patient is considered a diagnostic method and is therefore barred under Section 3(i). Furthermore, the distinction between 'screening' and 'diagnosis' is not determinative — screening tests can be 'diagnostic' if they identify a disease or condition for treatment.

Section 3(i) specifically targets the processes employed by medical practitioners, paramedical staff, and nurses and excludes them from patentability, reflecting a policy against monopolising treatment methods.

Crucially, the fate of an Indian Patent application is decided under national law. Reliance on the grant of a patent in a foreign jurisdiction like the USA or Europe carries no merit in the context of an Indian Patent.

Reliance was also placed on Chinese University of Hong Kong v. Assistant Controller of Patents & Designs² and Natera Inc. & Anr. v. Assistant Controller of Patents and Designs³. The same Bench in Sequenom Inc & Anr. v. The Controller of Patents⁴ further clarified that any technique helping a physician determine a course of medical treatment falls under the statutory bar for diagnostic processes.

Upon detailed examination, the Delhi High Court observed that the exclusion under Section 3(i) must be interpreted purposively — not narrowly. The Court emphasised that the term "diagnostic" cannot be confined merely to the identification of a disease, but must extend to processes that play a substantial role in helping determine the course of medical treatment, including those that guide or influence treatment choices.

The Court rejected the Appellant's attempt to distinguish the claimed invention as a mere "screening" method, holding that the patentability test in such cases lies in the functional outcome of the process. The impugned application involved obtaining a biological sample, measuring telomere length, comparing the results with a defined threshold, and using this information to determine whether a patient would benefit from a specific treatment — which the Court held constitutes an integral part of the diagnostic process directly related to therapeutic decisions.

The Court further clarified that the exclusion under Section 3(i) is not limited to in vivo processes — in vitro processes can equally fall within its ambit if they contribute to diagnosis or treatment. It also observed that smart claim drafting cannot exclude inventions performing functions of "diagnosis" or "treatment" from falling under Section 3(i). Mere labelling of a diagnostic process as "screening" cannot disguise what is fundamentally a diagnostic method guiding therapy selection.

The Delhi High Court's decision in Geron Corporation reinforces India's consistent position that methods influencing medical treatment decisions remain outside patent protection, regardless of clever drafting strategies. It gives a clear message: patent law must serve public health, not commercial cleverness. If the process helps a doctor decide how to treat a patient, it is diagnostic in substance — regardless of whether it happens in vivo or in vitro.

The Court emphasised that claim language cannot override the function of the invention and that clever drafting techniques cannot disguise the true nature of an invention.