Sugammadex's Process Patent Was Refused Without the Hearing India's Law Requires

Sugammadex is the active ingredient in Bridion, the drug anesthesiologists use to reverse the effects of the muscle relaxants rocuronium and vecuronium at the end of surgery. Structurally it is a modified gamma-cyclodextrin - a ring of eight glucose units - with eight thioether arms hanging off it, each one ending in a carboxylic acid. Those arms are what let the molecule wrap around and trap the muscle relaxant, and building them onto the cyclodextrin ring is where most of the process chemistry, and most of the patent fights, actually live.

Fresenius Kabi Ipsum Srl filed an Indian patent application in March 2016 for one specific way of building those arms: react 6-per-deoxy-6-per-halo-gamma-cyclodextrin (the halogenated ring, ready to be substituted) with an isolated disodium salt of 3-mercaptopropionic acid, in DMSO, at 70-75C, for four to five hours. The word doing the work there is "isolated." The closest prior art, an earlier application referred to as D1, makes essentially the same salt but never isolates it - it generates the thiolate in situ by adding thirty equivalents of sodium methoxide straight into the reaction with the acid, in DMF, at 75-80C, for twelve to fourteen hours.

Fresenius Kabi's argument was that pre-forming and isolating the salt as its own characterizable compound, rather than generating a transient thiolate in the same pot as everything else, cuts the reaction time roughly in half, needs far less strong base, and avoids a specific impurity the applicant says the in-situ route inherently produces. Whether that is actually true, and whether it clears India's inventive-step bar even if true, is exactly what never got decided here - and that is the point worth sitting with.

Justice Jyoti Singh's judgment, delivered 31 August 2026, did not rule on any of that. It set the refusal aside on a narrower, procedural ground: Section 14 of the Patents Act - the mandatory hearing between the Controller and the applicant once an examination report raises objections - is a separate statutory track from Section 25(1), the pre-grant opposition hearing a third party can trigger. Fresenius Kabi got a Section 25(1) hearing, because a party opposed the grant. It never got a Section 14 hearing on the examiner's own objections. The Controller apparently treated the opposition hearing as covering both. The court said that conflates two rights the statute keeps deliberately separate, calling the applicant's Section 14 right "not merely a procedural violation, but violation of a substantive right" - and pointed to the same principle already established in Novartis v. Natco (2024 SCC OnLine Del 152), that examination and opposition are independent processes that cannot substitute for one another.

That part is decided law now, cleanly, and it is worth being direct about it: a patent office that runs an opposition hearing and calls it a day, without giving the applicant its own separate statutory hearing on the examiner's objections, is not skipping a technicality - it is skipping a step the Act requires before a refusal can stand. Any applicant on the receiving end of a similar shortcut has a real, already-decided argument to point to.

So here is what is actually settled and what is not. Settled: an applicant is entitled to its own Section 14 hearing regardless of what happened in a Section 25(1) opposition, and an obviousness rejection that stacks documents without a stated starting point or a stated reason to combine them is vulnerable on that basis alone. Not settled, and not something this piece is going to guess at: whether isolating a reagent salt before use, instead of generating it in the same pot as the main reaction, is the kind of technical difference Indian patent law will treat as inventive here, or whether the Controller's "merely cosmetic" instinct will hold up on a properly reasoned second look. That is a real, open chemistry question, and it is exactly the kind of question that keeps coming up in API process patents generally - isolate-and-purify versus generate-in-situ is one of the most common design-around moves in the business, and this case is a reminder that whether it counts as invention rather than workaround still gets decided one molecule, one impurity profile, and one properly conducted hearing at a time.