In a recent decision of the High Court of Madras, in the Chinese University of Hong Kong and Sequenom, Inc. (“Appellants”) v. The Assistant Controller of Patents and Designs (“Respondent”), CMA (PT) No.14 of 2023, the Court had the opportunity to delve into the nuances of Section 3(i) of the Indian Patents Act, 1970 (as amended) (the ‘Act’), which deals with the patentability of processes 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.

In this case, an appeal was filed before the High Court, to set aside the order of the Respondent, in relation to Indian Patent Application No. 4812/CHENP/2012. At the Hearing held during the examination stage of the said application, the Appellants argued that the determination of the foetal fraction does not diagnose a disease and therefore, the claimed invention is not a diagnostic method, and hence, falls outside the scope of Section 3(i) of the Act. Consequently, it was argued, that the subject invention ought to be granted a patent. However, the Respondent held that paragraph [0007] of the complete specification of the subject application, sufficiently corroborates the fact that the present invention is a process of diagnosing a foetus suffering from genetic or other diseases. Consequently, the Respondent rejected the application, and held the instant invention qualifies as a diagnostic method under Section 3(i) of the Act, and is hence, not patentable.

On Appeal, the High Court found that the claimed invention is per se incapable of identifying the existence or otherwise of a disease, disorder or condition, and further testing would be required for such purpose. In effect, it provides an indicator, foetal fraction, which is relevant for further testing to arrive at a diagnosis. Further, although the determination of the foetal fraction was relevant to diagnosis, it did not possess an inherent “diagnostic” nature. This fraction was essential for subsequent tests aimed at diagnosing chromosomal abnormalities. Nonetheless, the court drew a significant distinction: the invention didn’t directly diagnose diseases, disorders, or conditions; instead, it furnished an indicator (i.e., the foetal fraction) pertinent to subsequent diagnostic examinations.

Further, the Court also made the following observations:

• The expression “diagnostic” should not be analysed in isolation, but rather in conjunction with the other terms set out in Section 3(i) of the Act. Further, the term “diagnostic” should be confined to diagnostic processes that reveal pathology and forms the basis of the treatment.
• If an expert in the relevant field, including medical professionals, analyse the claims in the context of the complete specification, and they are unable to diagnose a disease or condition based on the process, then such process should not be deemed to fall within the ambit of “diagnostic” under Section 3(i) of the Act.
• If a screening test can identify the existence or non-existence of a disease, disorder or condition including others for treatment of human beings then such screening test would qualify as a diagnostic test. In other words, the label used for the test – be it screening or anything else – is not determinative. Thus, Controllers should make a determination on a case-by-case basis to determine if the screening process is diagnostic or not.
• That Section 3(i) of the Act is not confined to in-vivo or in-vitro

This decision of the High Court is a pathbreaking precedent, especially for cases/situations where the distinction between the terms “diagnosis” and “diagnostic” ought to be carefully considered, underscoring the crucial criterion that a process must possess an inherent capacity to identify diseases or conditions for it to be prohibited under Section 3(i) of the Act.