Roche patent case: Why SC refused to halt Natco’s generic spinal muscular atrophy drug Risdiplam

Roche had approached Delhi High Court, accusing Natco of violating its Indian patent, before going to the Supreme Court with its petition.

Roche's main office in Switzerland. The firm had approached the court, seeking an interim injunction to restrain Natco from manufacturing and selling generic Risdiplam | Courtesy: roche.ch

New Delhi: The Supreme Court last week refused to grant interim relief to Swiss multinational drugmaker Roche, which alleged that Hyderabad-based Natco Pharma was infringing its patent for Evrysdi, with its own, generic formulation Risdiplam.

Both Evrysdi and Risdiplam are used to treat spinal muscular atrophy (SMA).

SMA is a rare genetic disorder that causes progressive muscle weakness and wasting due to the loss of motor neurons—the nerve cells controlling voluntary movement.

Roche’s Evrysdi is currently the only non-invasive, disease-modifying treatment for SMA. It is approved in over 100 countries, with the US Food and Drug Administration (US FDA) recognising it as the “first and only oral treatment” for the condition.

Roche approached the Supreme Court with a special leave petition, alleging that Natco’s version of the drug, Risdiplam, violated its Indian patent (IN 334397), which protects “compounds for treating SMA”.

The patent, valid until May 2035, grants Roche exclusive rights to manufacture and market the drug in India.

Before the Delhi High Court, Roche had earlier sought an interim injunction to restrain Natco from manufacturing and selling its generic version, and called for a final determination of the patent’s validity. However, a division bench of the High Court rejected Roche’s petition for the injunction on Natco earlier this month.

Now, a Supreme Court bench of Justices P.S. Narasimha and Atul Chandurkar have denied Roche interim relief, declining to interfere with the High Court’s decision. In refusing to intervene, the top court directed the high court to decide the suit “expeditiously.”

“We make it clear that the observations made in the FAO are intended only for its disposal and will have no bearing when the merits of the case are tried and decided. The high court shall make an endeavour to dispose of the suit expeditiously,” the SC said.

With the Supreme Court’s refusal to intervene, F. Hoffmann-La Roche’s last-ditch attempt to secure immediate relief has failed.

The Delhi High Court will now proceed to hear the full case to determine whether Roche’s patent is valid or should be revoked. Until then, Natco’s generic version will remain on the market—a major setback for Roche’s exclusive rights over the SMA treatment.

Case at hand

The dispute between the two pharma majors first reached the Delhi High Court in 2024, when Roche sued Natco for patent infringement.

Roche argued that Natco’s Risdiplam infringed its patented molecule for treating SMA and thereby violated its exclusive rights under Section 48 of the Patents Act, 1970, which grants a patentee the right to prevent others from making or selling the patented product without consent.

“…A patent granted under this Act shall confer upon the patentee… the exclusive right to prevent third parties, who do not have his consent, from the act of making, using, offering for sale, selling or importing for those purposes that product in India,” Section 48 (a) states.

Natco did not deny manufacturing and selling Risdiplam. Instead, it relied on Section 107(1) of the Act — a defence provision that allows an alleged infringer to challenge the validity of the patent itself. This meant that, rather than arguing it was not manufacturing the formulation, Natco contended that Roche’s patent was invalid and therefore not infringed.

Natco argued that Roche’s patent was invalid because the compound was “obvious” from earlier patents, specifically the genus patents WO 2013/119916 and US 9586955, which had already disclosed compounds that are in Risdiplam.

Under patent law, a patent can be revoked if it lacks an “inventive step” or the innovation is “obvious” to a person skilled in the art—meaning a trained chemist or scientist could have developed it using existing knowledge. This principle prevents companies from extending monopolies through minor or routine modifications to older inventions, in a practice known as “evergreening”.

What Delhi HC said

A single-judge bench of the Delhi High Court found, prima facie, that Roche’s compound was “obvious” in light of prior art. The judge noted that the difference between Roche’s Evrysdi and an earlier molecule, Compound 809, was merely the replacement of one carbon-hydrogen (–CH) group with a nitrogen (–N) atom, which, in turn, is a chemically predictable modification.

The court relied on Grimm’s hydride displacement law, which treats –CH and –N as “bioisosteres” (chemically equivalent groups), concluding that such a substitution would be “obvious” to a skilled chemist.

Since the same inventors were behind both the genus and species patents (Roche’s patent filing), the judge said the change did not amount to a genuine innovation. The court therefore refused to grant an injunction, allowing Natco to continue manufacturing and selling Risdiplam.

Roche appealed the single-judge decision, arguing that the court blurred the distinction between “coverage” (a compound falling within a broader class) and “disclosure” (a compound being specifically described). Roche contended that mere coverage under an earlier patent does not automatically make a new compound “obvious” or invalidate the later patent.

A division bench of Justices C. Hari Shankar and Ajay Digpaul, however, upheld the single-judge’s ruling.

While the bench noted that it had doubts about whether the patent was fully “disclosed” in the earlier patents, it agreed that Roche’s compound appeared “obvious”, which was sufficient to deny interim relief.

“The learned single judge, in a judgment crafted with clinical precision, has upheld the defence raised by the respondent, predicated on Section 64(1)(e) and (f) of the Patents Act,” the division bench said, referring to the statutory grounds for revocation of patents.

The judges also noted that four of the inventors were common to both patents, suggesting the modification was not inventive enough to justify a fresh 20-year monopoly—the standard patent term.

The division bench relied on the landmark Wander Ltd. v. Antox India Pvt. Ltd. (1990) case, holding that in appellate jurisdiction, the question was only whether the legal principles had been applied correctly, not to re-evaluate the factual findings.

Applying those principles, the bench concluded it would not interfere with the single-judge’s discretionary order since Natco had raised a credible challenge to Roche’s patent under Indian patent law.

(Edited by Madhurita Goswami)