A recent Delhi High Court judgment in Zeria Pharmaceutical Co. Ltd. vs. The Controller of Patents (C.A.(COMM.IPD-PAT) 452/2022) delivers a message to the pharmaceutical industry: a higher yield and greater purity are not enough to secure a patent in India.

Zeria’s patent application for a novel intermediate compound was rejected by the Indian Patent Office, and the High Court upheld that refusal on two critical grounds

• Lack of inventive step and,
• Failure to satisfy Section 3(d) of the Indian Patents Act, 1970

Zeria Pharmaceutical Co. Ltd. vs. The Controller of Patents – Basic Details:

• Title: ZERIA PHARMACEUTICAL CO. LTD. vs. THE CONTROLLER OF PATENTS
• Court: High Court of Delhi at New Delhi
• Case Number: C.A.(COMM.IPD-PAT) 452/2022
• Date of Judgment Pronounced: May 27, 2025
• Appellant: Zeria Pharmaceutical Co. Ltd.
• Respondent: The Controller of Patents
• Patent Application: Indian Patent Application No. 3630/DLNP/2011 titled “A COMPOUND REPRESENTED BY FORMULA (5a)”, filed as a divisional out of Indian Patent Application 1090/DELNP/2007.

Zeria Pharmaceutical Co. Ltd. vs. The Controller of Patents – The Core Issue: Obvious Modification, Not Innovation:

The compound in question was structurally very similar to a known substance in the prior art the only difference being the substitution of a “methoxy group” with an “ethoxy group”.

The Court agreed with the Controller that such a minor modification represented routine experimentation that any skilled chemist could have performed. Hence, it failed to qualify as an inventive step under Section 2(1)(ja) of the Patents Act.

This finding once again underscores India’s stringent approach toward incremental pharmaceutical innovations, especially when structural differences are minor and predictable.

Zeria Pharmaceutical Co. Ltd. vs. The Controller of Patents – Patent Refusal Grounds:

• Application was refused under Section 2(1)(ja) (inventive step) and Section 3(d) (new form of known substance without enhanced efficacy) of the Patents Act, 1970.
• Prior art documents considered: D1 (EP 0994 108 A1, Zeria Pharma Co. Ltd.) and D2 (US 5981 557 A, Nagasawa Masaaki et al).

Zeria Pharmaceutical Co. Ltd. vs. The Controller of Patents – Arguments by Appellant (Zeria):

• Controller misunderstood the technical problem and solution.
• D1 teaches away from the claimed invention and was marked as “A” category in the International Search Report.
• D2 does not specifically describe the claimed methyl ester.
• Claimant argued non-obviousness, highlighting the required selections to arrive at the claimed compound.
• Controller did not consider expert data showing inventive step.
• Superior properties of the claimed intermediate compared to the prior art were argued.

Zeria Pharmaceutical Co. Ltd. vs. The Controller of Patents – Understanding the Implications for Patent Law

Zeria Pharmaceutical Co. Ltd. vs. The Controller of Patents – Arguments by Controller:

• D2 differs only in having an ethoxycarbonyl group instead of the claimed methoxycarbonyl group.
• D2 and D1 cover lower alkoxy groups for the relevant positions, including methoxy/ethoxy.
• Claimed compound is considered merely a new form/derivative of a known compound (covered under Section 3(d)).
• No enhanced efficacy demonstrated by applicant.

Zeria Pharmaceutical Co. Ltd. vs. The Controller of Patents – Court’s Analysis:

• Section 3(d) excludes new forms of known substances unless significant efficacy enhancement is shown.
• Enhanced therapeutic efficacy is mandatory, especially for medicines—physicochemical improvements are insufficient.
• The data submitted did not demonstrate enhanced therapeutic efficacy, only higher yield and lower impurities which are not enough under Section 3(d).
• The inventive step assessment found that the claimed compound is obvious, since substitution of ethoxy to methoxy is routine experimentation for a skilled person.
• The prior art provides sufficient motivation for a skilled person to arrive at the claimed compound.
• Appellant’s arguments about “teaching away” were rejected since mere teaching of one solution does not preclude another.

Zeria Pharmaceutical Co. Ltd. vs. The Controller of Patents – Key Takeaways for Innovators and IP Professionals:

• Efficacy Must Be Therapeutic: When filing patents for derivatives or analogs of known compounds, applicants must present solid clinical or pharmacological data proving improved therapeutic action. Manufacturing improvements or better yields won’t meet the Section 3(d) requirement.
• Obviousness Remains a High Hurdle: Minor, predictable chemical substitutions (like replacing similar functional groups) rarely qualify as inventive. Patent claims must reflect a genuine technical advance beyond standard optimization.
• Strategic R&D and Prosecution Are Crucial: Indian patent law demands a data-driven, evidence-based approach from the research stage itself. Companies should plan early to generate efficacy data aligned with India’s strict patentability criteria.

Zeria Pharmaceutical Co. Ltd. vs. The Controller of Patents – Implications for the Pharmaceutical Industry:

This ruling reinforces India’s strong stance against evergreening and its commitment to balancing innovation with public access to medicines. It also acts as a practical guidepost for patent applicants especially multinational pharmaceutical companies accustomed to more lenient patent standards elsewhere.

This case also emphasizes the need for strategic patent drafting, rigorous data generation, and clear differentiation from prior art to withstand scrutiny under Indian patent law.

Zeria Pharmaceutical Co. Ltd. vs. The Controller of Patents – Conclusion:

Zeria Pharmaceutical decision stands as another reminder that India’s patent system prioritizes true therapeutic innovation over mere improvements in process efficiency or purity. For researchers, innovators, and patent practitioners, this ruling highlights the importance of aligning R&D, patent strategy, and data generation to meet India’s distinct legal thresholds.

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