Section 3(d) of the Indian Patent Act 1970 prohibits the grant of patents for 
inventions that are mere enhancements of known substances, unless such 
enhancements result in a significant improvement in efficacy.
This provision aims to strike a balance between promoting innovation and 
ensuring affordable access to essential medicines, particularly in the context 
of pharmaceutical patents. The interpretation of Section 3(d), particularly 
regarding the criterion of therapeutic efficacy, has been the subject of several 
legal disputes and judicial pronouncements.
Case Overview
The case under consideration before the Hon'ble Division Bench, High Court of 
Delhi, involved an appeal challenging the validity of a patent (IN-176) granted 
for a medicinal product. The central issue before the Court was whether the 
properties of enhanced solubility and bio availability, claimed by the 
applicant, could be construed as evidence of higher therapeutic efficacy, thus 
satisfying the requirements of Section 3(d). The appellant argued that the 
enhanced bioavailability of the patented product did not necessarily translate 
to a higher therapeutic efficacy, as claimed by the patent holder.
Judgment Analysis:
In its analysis, the Hon'ble Division Bench, High Court of Delhi provided 
clarity on the interpretation of Section 3(d) and its application to 
pharmaceutical patents. The Court emphasized that the test of efficacy under 
Section 3(d) should be limited to therapeutic efficacy, rather than considering 
other properties such as enhanced solubility and bioavailability.
The Court reasoned that while enhanced bioavailability might contribute to the 
effectiveness of a medicinal product, it does not automatically imply a higher 
therapeutic efficacy.
Furthermore, the Court noted that the applicant had not claimed any enhancement 
in therapeutic efficacy in its patent application. Instead, the sole advantage 
claimed was related to enhanced solubility and bioavailability.
Based on these observations, the Court concluded that the appellant had raised a 
credible challenge to the validity of the patent (IN-176), as the claimed 
properties did not establish a significant improvement in therapeutic efficacy 
as required under Section 3(d).
Implications and Conclusion
The judgment provides valuable guidance on the interpretation and application of 
Section 3(d) of the Indian Patent Act 1970, particularly in the context of 
medicinal patents. By clarifying that the test of efficacy is limited to 
therapeutic efficacy and cannot be extended to properties like enhanced 
solubility and bioavailability, the Court reaffirmed the legislative intent 
behind Section 3(d) to prevent the grant of patents for mere incremental 
improvements of existing substances.
The Case Discussed:
Case Title: Natco Pharma and Novartis AG and another
Judgment/Order Date: 24.04.2024
Case No:FAO OS Comm 178 of 2021
Neutral Citation: 2024:DHC:3198
Name of Court: Delhi High Court
Name of Hon'ble Judge: Vibhu Bakhru and Amit Mahajan,H.J.
Disclaimer:
This article is meant for informational purposes only and should not be 
construed as substitute for legal advice as Ideas, thoughts, views, information, 
discussions and interpretation perceived and expressed herein are are subject to 
my subjectivity and may contain human errors in perception, interpretation and 
presentation of the fact and issue of law involved herein.
Written By: Advocate Ajay Amitabh Suman, IP Adjutor - Patent and 
Trademark Attorney
Email: 
[email protected], Ph no: 9990389539
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