Delhi High Court Rejects Roche’s Patent Infringement Appeal, Allowing Natco to Continue Selling Spinal Muscular Atrophy Drug Risdiplam
Sanchayita Lahkar
The High Court of Delhi, Division Bench of Justice C. Hari Shankar and Justice Ajay Digpaul on Thursday dismissed an appeal by Swiss pharmaceutical major F. Hoffmann-La Roche AG, thereby affirming the Single Judge’s refusal to grant an interim injunction against Natco Pharma Ltd in a patent dispute concerning Risdiplam, a drug used to treat Spinal Muscular Atrophy. The Court upheld the finding that Natco’s manufacture and sale of the drug did not warrant injunctive relief, as Roche’s suit patent IN’397—covering compounds for treating the condition and valid until 2035—was found vulnerable to invalidation on the ground of obviousness under Section 64(1)(f) of the Patents Act.
The dispute arose between F. Hoffmann-La Roche AG, a Swiss pharmaceutical company, and Natco Pharma Limited, an Indian generic drug manufacturer, over the manufacture and sale of Risdiplam, a medicine used for treating Spinal Muscular Atrophy (SMA). Roche claimed rights over Indian Patent IN’397, which covered certain compounds for the treatment of SMA and was stated to be valid until May 2035. Roche alleged that Natco’s manufacture and sale of Risdiplam infringed this patent and sought an interim injunction to restrain the company from continuing its activities.
Natco denied infringement and questioned the validity of Roche’s patent, asserting that it lacked novelty and inventive step. It contended that the claimed compound was anticipated and rendered obvious by earlier disclosures in prior art, particularly in patents WO’916 and US’955, which also described similar compounds for treating SMA. Natco argued that the only difference between the compound claimed in IN’397 and Compound 809 disclosed in the prior art was the replacement of a carbon-hydrogen radical with a nitrogen atom—an alteration that would have been apparent to a person skilled in the art. The company also pointed out that several inventors were common to both the earlier and later patents, suggesting continuity in the development process rather than a distinct inventive advance.
Roche maintained that Risdiplam represented an inventive and distinct molecule not disclosed in the prior patents and that the compound achieved improved therapeutic efficacy. It relied on its experimental data and patent specifications to demonstrate novelty and inventive step.
The Single Judge examined the parties’ submissions, prior patent disclosures, and expert opinions, concluding that Natco had raised a credible challenge to the validity of the suit patent. Finding no strong prima facie case for infringement, the Court dismissed Roche’s application for interim injunction. Roche appealed this decision before the Division Bench of the Delhi High Court.
The Bench stated that its jurisdiction was “circumscribed by the exposition of law in Wander Ltd v Antox India (P) Ltd,” adding that “the appellate court will not interfere with the exercise of discretion of the court of first instance unless it was arbitrary, capricious, or perverse.”
On novelty, the Court observed that Section 64(1)(e) applies “where the claim in the suit patent is not new and has been claimed in prior art.” The Bench recorded that the respondent’s contention was that Risdiplam was “one of the compounds covered by the Markush formulation disclosed in the genus patent.” While noting the divergence of judicial opinion on whether “coverage” equates to “disclosure,” Justice Hari Shankar stated that “mere coverage of the compound claimed in the species patent within the broad Markush claim in the genus patent would not ipso facto amount to disclosure, unless the genus patent contains the requisite teaching” to enable a person skilled in the art to arrive at the species compound.
Addressing obviousness, the Bench held: “Obviousness has to be decided by examining whether a person skilled in the art would, from the teachings contained in the genus patent and common general knowledge, be able to arrive at the claim in the species patent.” The Court agreed with the Single Judge’s finding that the difference between Risdiplam and Compound 809 in the genus patent “is merely of a Nitrogen (-N) atom in the case of Risdiplam and a -CH radical at the same junction in Compound 809.”
The Bench further cited the “person in the know” test evolved in AstraZeneca AB v. Intas Pharmaceuticals Ltd., observing that where the inventors of both the genus and species patents are common, “the aspect of obviousness would have to be assessed from the perspective of the inventor, who would be a person conscious of the specifics of the invention.” It found this principle “logically sound,” noting that “something which is ‘obvious’ to a person skilled in the art would, therefore, be ‘more obvious’ to the inventor of the genus patent, who would be ‘in the know’.”
The Court cited several scientific considerations that, in its view, supported the Single Judge’s findings. It noted that the genus patent “disclosed different chemical structures with Nitrogen placed at different positions,” and that “using the same kind of ring varying the number of Nitrogen atoms and positions is obvious for a person skilled in the art.” Referring to Grimm’s Hydride Displacement Law, the judgment recorded: “Nitrogen (N) and CH groups are often considered bioisosteres... substitution of a CH group with a Nitrogen (N) atom which are bioisosteres, would be obvious to a person skilled in the Art of medicinal chemistry.”
The Bench stated that, because four of the lead inventors were common to both patents, there was “legitimate basis to presume that they would be possessed of the requisite degree of knowledge to select Compound 809 from the exemplified compounds in the genus patent as the compound to be worked upon or modified to arrive at Risdiplam.” It held that allowing the later patent would risk “evergreening,” stating that “by making changes to an invented pharmaceutical preparation which is essential or life-saving in nature, [an inventor] cannot keep the invention out of the public domain beyond the period of life of the patent.”
The Court concluded that the Single Judge “has applied the correct principles,” and that “within the parameters of our jurisdiction as circumscribed by Wander, we do not feel that a case has been successfully made out... as would justify our interference with the prima facie findings of the learned Single Judge.”
The Division Bench stated: “We have found the judgment of the learned Single Judge, that the respondent had succeeded in setting up a credible challenge to the validity of the suit patent, within the meaning of Section 107 read with Section 64 of the Patents Act, worthy of acceptance.” The Bench accordingly held that “this is not a fit case for interference with the impugned judgment.”
“We, therefore, do not deem this to be a fit case for interference with the impugned judgment of the learned Single Judge. The appeal is, accordingly, dismissed.”
Advocates Representing the Parties:
For the Appellants: Mr. Sandeep Sethi, Senior Advocate with Mr. Pravin Anand, Ms. Archana Shanker, Mr. Shrawan Chopra, Ms. Prachi Agarwal, Mr. Devinder Rawat, Mr. Achyut Tewari, Ms. Elisha Sinha, Ms. Krisha Baweja, Mr. Aayush Maheshwari, Mr. N. Mahabir, Ms. Shreya Sethi and Mr. Sumer Seth, Advocates.
For the Respondent: Mr. J. Sai Deepak, Senior Advocate with Mr. Afzal B. Khan, Mr. Samik Mukherjee, Mr. Dominic Alvares, Ms. Amrita Majumdar, Mr. Avinash K. Sharma and Mr. Sharad Besoya, Advocates.
For the Interveners: Mr. Sethi Grover, Senior Advocate with Mr. Varun Jain and Mr. Rohin Bhatt, Advocates; Ms. Rajeshwari H., Ms. Purva Mittal and Mr. Tahir A. J., Advocates.
Case Title: F. Hoffmann-La Roche AG & Anr. v. Natco Pharma Limited
Neutral Citation: 2025: DHC:8943-DB
Case Number: FAO(OS)(COMM) 43/2025
Bench: Justice C. Hari Shankar and Justice Ajay Digpaul
