Introduction

On 9 October 2025, the Delhi High Court delivered a judgement in F. Hoffmann-La Roche Ag & Anr vs Natco Pharma Limited that effectively dismantled the traditional wall between broad ‘genus’ patents and specific ‘species’ patents. The legal battle over Risdiplam is not just about a chemical compound, it is a story about the price of a human life and the limits of how long a company can keep a secret. By refusing to stop Natco from selling a generic version of a drug used to treat Spinal Muscular Atrophy (SMA), the court essentially ruled that when a multi-billion pound company tries to extend its monopoly through tiny, predictable tweaks, the public’s right to affordable medicine must come first. This case signals a shift away from a purely mechanical view of innovation and toward a standard that looks at who is doing the inventing and why they chose a specific path.

The single atom swap and the shadow of the genus patent

To understand why this case matters, we have to look at the chemistry, which is surprisingly simple. Spinal Muscular Atrophy is a brutal genetic disease that withers the muscles of infants and children. Until recently, treatments were invasive and incredibly expensive. Roche’s drug (Risdiplam) changed that by being an oral solution. However, that convenience came at a cost of roughly ₹6 lakh per bottle, making the annual cost of treatment nearly ₹72 lakh for a single patient. When Natco Pharma announced a version for ₹15,900, the stakes shifted from legal theory to biological survival.

Roche’s legal strategy relied on Indian Patent No. 334397, which specifically claims Risdiplam. But here is the catch, Roche had already filed a much broader genus patent (WO 916) years earlier. That earlier patent included a molecule known as Compound 809. If you look at the structure of Compound 809 and Risdiplam side-by-side, they are identical except for one single spot. Compound 809 has a methine group (carbon and hydrogen), while Risdiplam has a nitrogen atom. The entire dispute rested on whether swapping a carbon-hydrogen group for a nitrogen atom was a breakthrough or just a routine afternoon’s work in a lab.

The court decided it was the latter. Justice C. Hari Shankar pointed out that these two groups are ‘bioisosteres,’ chemical twins that the body treats almost identically. Drawing on a century-old principle called Grimm’s Hydride Displacement Law, the court noted that this swap is a standard trick used by medicinal chemists to make drugs easier for the body to absorb. Because the earlier genus patent already talked about using these kinds of rings, the court found that the new patent was likely obvious and therefore vulnerable to being scrapped. This finding of obviousness under Section 64(1)(f) rendered the species patent vulnerable to revocation, as any chemist looking to optimize Compound 809 would naturally consider substituting the methine group with a nitrogen atom.

Why the identity of the scientist changes everything

The most controversial part of this judgement, and the one that will keep patent lawyers up at night, is the ‘Person in the Know’ test. In most patent cases, the court asks if an invention would be obvious to a ‘Person Skilled in the Art’ (PSITA). This is a hypothetical, average chemist who is smart but not a genius. However, the Delhi High Court noticed something interesting that four of the scientists who invented the first broad patent were the exact same people who invented the second, more specific one.

This changed the rules of the game. The court argued that we cannot pretend these scientists are average, uninformed chemists. They are ‘Persons in the Know’ and had intimate, private access to their own data, their own failures, and their own research journey. Because they were already working with Compound 809, it was much more likely for them to try the nitrogen swap. Something which is obvious to a person skilled in the art would, therefore, be even more obvious to the inventor of the genus patent, who would be in the know of all the angularities and peculiarities of their own earlier work.

This is a huge deal for pharmaceutical companies. Usually, companies use one team to find a broad class of drugs and then use that same team to pick the best one. The court is now saying that this continuity actually makes it harder to get a second patent. By attributing the inventors personal knowledge to the legal test for obviousness, the court has created a massive hurdle for evergreening. It is a move that prioritises transparency over corporate strategy and ensures that companies cannot use their internal, incremental iterations to extend monopoly protection indefinitely.

International games and the end of double-dipping

For years, innovators have played a game of Goldilocks with patent drafting. They want their first patent to be broad enough to cover every possible competitor but vague enough not to disclose the exact drug they want to patent later. Roche tried to argue this exact point, that while Risdiplam was covered by their old patent, it was not disclosed.

The court essentially told Roche they could not have it both ways. The judgement noted that Roche had told the American authorities that Risdiplam was covered and disclosed by their old patents to get a patent term extension in the US. The court found it inequitable for a company to claim a drug is old in America to get more time, while claiming it is new in India to get a fresh patent. This insistence on international consistency strikes a blow against the strategies that have allowed pharmaceutical giants to dominate markets for decades. If a compound is covered by the Markush claims of a genus patent and is structurally similar to an exemplified compound, the burden on the patentee to prove a non-obvious inventive step becomes nearly insurmountable.

The balance of survival

The socio-political heart of this case is the ‘balance of convenience’ test. In an injunction suit, the court has to decide who will be hurt more if the drug stays on or off the market while the trial proceeds. Roche argued that they would suffer irreparable harm if Natco was allowed to sell a cheaper version, as it would destroy their market and their incentive to innovate.

The court’s response was a blunt reality check. They ruled that the harm to Roche was purely financial and could be calculated in pounds later if Roche won the final trial. However, the harm to a child with SMA who cannot afford a ₹6 lakh bottle of medicine is irreversible. Motor function lost cannot be bought back. The court explicitly stated that when a drug is not available at a reasonably affordable price, the public interest outweighs the patentee’s right to an injunction. This pricing disparity of nearly 97% provided the inescapable economic context for the legal arguments.

This is a powerful constitutional statement. It reinforces the idea that in India, a patent is not an absolute property right but a social contract. If the patentee does not provide the drug at a fair price, the state will not protect their monopoly during a legal dispute. This is especially true when the patent itself is built on shaky chemical foundations. By manufacturing in India rather than just importing, Natco also aligned its interest with national policies of self-reliance, further strengthening its position.

A new roadmap for generic strategy

Finally, the case highlights a new procedural standard for generic manufacturers, the ‘Clearing the Way’ doctrine. In the past, many Indian companies would simply launch at risk and hope for the best. But as we saw in the parallel FMC Corporation v Natco case, the court is now rewarding companies that are proactive. Natco won here partly because they filed a revocation petition to challenge Roche’s patent before they launched their product. By being transparent and challenging the patent through the legal system first, Natco demonstrated what the court calls bona fides. This is a sharp contrast to cases where companies launch in secret and get hit with injunctions for procedural bad faith. The message is clear, if you want to avoid an injunction, you must challenge the patent’s validity before you put your product on the shelves.