Delhi High Court Upholds Rejection Of Patent For Cancer Screening Method, Calls It Non-Patentable Diagnostic Process

Justice Manmeet Pritam Singh Arora, on March 17, 2026, held that the proposed “in vitro screening method” functions as a diagnostic process, which is barred from patentability under Section 3(i) of the Patents Act.

The court observed that regardless of whether a test is labeled as "screening" or conducted outside the human body, it remains a non-patentable diagnostic if it inherently enables a medical practitioner to make a treatment decision.

The bench noted that “it could be concluded that the subject matter claimed in the Subject Patent Application, though drafted as an 'in vitro screening method', is in substance a method for selecting cancer patients/suspected cancer patients who will benefit from treatment with a telomerase inhibitor, based on the determination of telomere length and application of a percentile threshold.”

Therefore, the court held that “the subject matter covered in the claims of the Subject Patent Application, when read along with the detailed description provided therein, covers a diagnostic process that forms the basis of the treatment of human beings. In view of Section 3(i) of the Patents Act, as clarified in the Manual, the Guidelines, and various decisions, the claimed methods are not patentable.”

Geron Corporation had contended that its invention is merely an in vitro technique used to identify which individuals—already diagnosed with or suspected of having cancer—would benefit from treatment with a telomerase inhibitor.

The biopharmaceutical company pleaded that the method does not identify the disease itself, but rather measures telomere length to determine drug response. Counsel for the company argued that the Assistant Controller of Patents had incorrectly characterized the invention as a diagnostic method, failing to follow internal guidelines which define diagnosis as the identification of the nature of a medical illness.

Geron further pleaded that the same invention had been granted patents in other major jurisdictions like the US and Europe, where in vitro diagnostic methods are permissible.

Conversely, the Assistant Controller of Patents and Designs pleaded that the invention squarely falls within the statutory bar because it identifies a diagnostic marker to guide medical therapy. It was contended that the assessment of telomere length is done specifically to determine if a patient should receive telomerase inhibition therapy, making it an integral part of the clinical treatment process.

Section 3(i) of the Patent Act does not distinguish between in vivo and in vitro processes, meaning tests conducted on biological samples are equally excluded if they serve a diagnostic purpose.

The Bench observed that the word "diagnostic" must be understood in the context of treatment; if a process is inherently capable of enabling a diagnosis for treatment, it is patent-ineligible.

The court remarked that while the biopharmaceutical company used the label "screening," the standard for patentability depends on the substance of the claim rather than drafting labels.

Since the method involves comparing a patient's data with a standard to decide on a course of therapy, the Court held it constitutes a diagnostic process that cannot be monopolized.

The Court observed that granting a patent in this case would unfairly restrict doctors from using a threshold rule to select patients for cancer therapy.

While acknowledging that foreign jurisdictions may have different rules, the Bench held that Indian patent law is governed by its own unique statutory exclusions intended to ensure public access to healthcare.

Consequently, the High Court dismissed the appeal, concluding that there was no error in the Controller's finding that the screening method was a non-patentable diagnostic process.

For Geron: Advocates Sanjeev Kumar Tiwari & Shatadal Ghosh

For Assistant Controller: CGSC Pratima N Lakra with Advocates Kanchan Shakya, Shailendra Kumar Mishra, Priyam Sharma & Chanakya Kene