Summary
The Delhi High Court upheld the Single Judge’s refusal to injunct Natco, holding that Roche’s Risdiplam claim is prima facie obvious over its own genus patents. The Bench corrected the novelty analysis but left the obviousness finding intact, narrowing Roche’s leverage and clearing the runway for generic entry—subject to the Supreme Court’s next word.
The Delhi High Court, in a judgment dated October 9th 2025, upheld the Single Judge’s refusal to grant F Hoffmann-La Roche AG an injunction against Natco Pharma Ltd., finding that Roche’s patent for Risdiplam was prima facie vulnerable to invalidation on grounds of obviousness under Section 64(1)(f) of the Patents Act, 1970. The Court clarified that while mere coverage of a compound in a genus patent does not amount to disclosure, the close structural similarity between Risdiplam and Compound 809 in the prior genus patent, along with common inventors and similar chemical teachings, made the later patent prima facie obvious.
Background
The dispute arose between F. Hoffmann-La Roche AG (“Roche”), a Swiss biopharmaceutical company, and Natco Pharma Limited (“Natco”), an Indian generic drug manufacturer, over the manufacture and sale of Risdiplam, a medicine used to treat Spinal Muscular Atrophy (SMA). Developed and marketed under the brand name Evrysdi, Risdiplam is the only oral therapy for SMA and is protected in India under Patent No. IN 334397, valid until May 11, 2035. Roche alleged that Natco’s activities infringed this patent and sought an interim injunction restraining the company from manufacturing or selling the drug.
In response, Natco denied infringement and challenged the validity of the Roche’s patent on multiple grounds, including anticipation by prior publication [Section 64(1)(e)], obviousness [Section 64(1)(f)], and misrepresentation [Section 64(1)(j)], relying on Roche’s earlier genus patents, WO 2013/119916 A2 (WO’916) and US 9,586,955 (US’955), which claimed Markush structures for compounds intended to treat SMA.
In the judgment dated March 24, 2024, the Single Judge refused interim relief, holding that Natco had raised a credible challenge to the validity of Risdiplam patent under Sections 64(1)(e) and 64(1)(f) of the Patents Act (see detailed case note here). The Court accepted Natco’s contention that Risdiplam was encompassed within the Markush structure disclosed in Roche’s genus patents and found that Claim 1, which specifically claimed Risdiplam, was obvious in view of Compound 809 disclosed in WO’916 / US’955. It observed that the only structural difference between the two compounds was the substitution of a –CH group in Compound 809 with a Nitrogen (–N) atom in Risdiplam, rendering them otherwise chemically identical.
Roche subsequently appealed against the decision before the Division Bench of the Delhi High Court.
Key Issues
- Whether Risdiplam lacked novelty based on disclosure or claiming in the prior genus patents (WO’916 / US’955).
- Whether Risdiplam lacked an inventive step, i.e., whether it was obvious to a person skilled in the art in view of the genus patents and common general knowledge.
- Whether the Single Judge’s findings warranted appellate interference under the standard established in Wander Ltd v Antox India (P) Ltd.
Court’s Observations
Novelty (Section 64(1)(e))
The Division Bench disagreed with the Single Judge’s finding that Risdiplam lacked novelty under Section 64(1)(e). It observed that mere inclusion of a compound within a broad Markush or genus formulation does not constitute specific disclosure. The Court noted that for a species patent to lack novelty, the prior art must clearly and unambiguously enable a person skilled in the art to synthesize the claimed compound. While Risdiplam fell within the broad Markush structure of Roche’s earlier patents, there was no explicit disclosure of the compound itself. The Court clarified that coverage relates to potential infringement, where a compound falling within a broad Markush claim may trigger liability, whereas disclosure relates to invalidity, requiring prior art to specifically enable a skilled person to arrive at a compound, and that mere coverage alone is insufficient to establish lack of novelty.
Inventive Step / Obviousness (Section 64(1)(f))
The Division Bench did not find any reason to interfere with the Single Judge’s finding that the claim for Risdiplam in the suit patent is prima facie vulnerable to invalidation under Section 64(1)(f) for obviousness. It noted that Risdiplam and Compound 809 shared an almost identical molecular structure, differing only by the substitution of a –CH group with a Nitrogen (–N) atom, a bioisosteric replacement commonly known in medicinal chemistry. Given the common inventors and similar chemical teachings across both patents, the Court maintained that a person skilled in the art, or “person in the know”, could have arrived at Risdiplam through routine structural optimization.
Standard of Appellate Interference (Wander Ltd. v Antox India Pvt. Ltd.)
Applying the Wander principle, the Court reiterated that appellate interference with a Single Judge’s discretionary order is limited to cases involving misapplication of law, failure to consider relevant factors, or perversity in reasoning. The Division Bench found that the Single Judge had applied the correct legal tests and had reasonably concluded that Natco had made a credible prima facie challenge to Roche’s patent. Accordingly, the Court found no basis for appellate interference.
Conclusion
The Court upheld the findings of the learned Single Judge and dismissed Roche’s appeal. This decision effectively paves the way for affordable generic Risdiplam to enter the Indian market. However, Roche has now approached the Supreme Court, seeking to restrain Natco from selling its generic version of the drug. The final outcome will depend on how the Supreme Court addresses the issue.
Citation: F. Hoffmann-La Roche Ag & Anr vs Natco Pharma Limited, 9 October, 2025
Available at https://indiankanoon.org/doc/161933978/
Article Review: Dr. Vasundhara Paliwal
