Vifor International Ltd & Anr. v. Corona Remedies Pvt Ltd & Anr.

Posted On - 27 February, 2024 • By - King Stubb & Kasiva

In a groundbreaking verdict on patent law, the Delhi High Court has clarified the legal stance on “product by process” claims and patent claim construction in India. The court, through its Division Bench in a detailed 188-page order on February 7, 2024, allowed the appeals by Vifor (International) Ltd., overturning the previous judgment by a Single Judge. The earlier ruling, dated July 24, 2023, had interpreted product-by-process claims as limited by the specific process mentioned, contending that protection extended only to products made using that particular process. The recent judgment rejects this view, asserting that patent protection for “product by process” claims encompasses the product itself, irrespective of the manufacturing process, as long as the product is novel and inventive. This significant development arose from Vifor’s appeal against the denial of an injunction by the Single Judge, involving generic pharmaceutical manufacturers in a patent dispute over Ferric Carboxymaltose (“FCM”). The court’s clarification ensures a more inclusive and expansive interpretation of product-by-process claims in the Indian patent landscape.

Case Facts

The case involves a dispute related to a patent (IN’536) held by the appellants, who are a part of the Vifor Pharma Group of Companies. The patent pertains to a water-soluble iron carbohydrate complex, specifically used for intravenous treatment of iron deficiency and iron deficiency anaemia. The product in question is FCM designed to be non-toxic, easily administrable, and capable of quick sterilization. The appellants argue that the prior art involved iron preparations based on sucrose and dextran, which had stability issues during sterilization.

The IN’536 patent application was filed on May 24, 2005, and granted on June 25, 2008, with a date of expiry on October 20, 2023. The appellant claims that the patent has counterparts in 57 jurisdictions worldwide, and neither the suit patent nor its foreign counterparts have faced successful challenges in pre or post-grant oppositions or legal proceedings. The appellant asserts that the patent was not challenged in pre-grant opposition in India. While the patent expired in 2023, the appellants claim to have exploited the monopoly granted by the patent for 12 of its 20-year term. The case includes details of various suits initiated by the appellants to protect IN’536, with a history of interim and final orders, including interim injunctions and settlements.

In terms of claims, the appellants argue that Claim 1 is an independent product claim for FCM, described by reference to an illustrative process, while Claims 2 to 6 embody illustrative processes for making FCM. The central contention is that FCM is a new and novel man-made product unknown in the prior art. The case also highlights the extensive litigation history where the appellants pursued legal actions against entities allegedly infringing on their patent rights, obtaining interim and permanent injunctions in some instances.


Whether the claims in question should be construed as product claims or process claims?

Arguments Advanced


  1. The appellants rely on a 2012 judgment (Ju) 120418 from the Supreme Court of Japan, emphasizing that the claim in a patent application plays a pivotal role in determining the technical scope of the patented invention.
  2. A comparative table is presented, scrutinizing parent and divisional patents (IN 221536, EP 1554315, US7612109, EP2278204, US20140371169, US20160215071), with the appellants asserting that divisional applications align with independent product-by-process claims.
  3. The timeline of divisional filings is explained, attributing the necessity of cautionary filings to the change in US law post the Abbott Laboratories decision in 2009.
  4. Allegations of manifest illegality are raised, contending that the learned Single Judge failed to consider favourable orders from nearly 20 lawsuits, which, according to the appellants, should have influenced the grant of an interim injunction.
  5. The appellants argue that the learned Single Judge misunderstood the nature of their claim, asserting that Claim 1 is not solely a process claim but a product claim, as consistently stated.
  6. The appellants emphasize that the balance of convenience is in their favour, citing equivalent patents across 57 jurisdictions and over 20 years of unchallenged protection as factors supporting their case.


  1. The defendants contend that the patent in question essentially constitutes a product-by-process claim. They argue that the novelty of the product is intrinsically tied to the process of oxidation, emphasizing that the oxidation step is pivotal for achieving the desired characteristics of low toxicity and prevention of anaphylactic shocks.
  2. The defendants stress the significance of the term “oxidized” and advocate for its broad interpretation to encompass colouration resulting from the oxidation process. They assert that this interpretation aligns with the true essence of the claimed invention.
  3. Emphasizing differences in their product, the defendants assert that their formulation utilizes a shell composed of hydrolyzed starch rather than maltodextrin. This distinction, they argue, is crucial in establishing non-infringement, as their product employs starch with a different DE value.
  4. Defendants contend that INN (International Nonproprietary Name) is a generic and common term intended for public use throughout the product’s life. They argue that the term FCM (iron carbohydrate complex) is also generic, and as their product is derived from starch, it should rightfully be labelled as FCM.
  5. Defendants assert that the patent primarily revolves around the process of obtaining the iron carbohydrate complex. They argue that protection should be limited to process elements rather than extending to the product itself.
  6. The interveners stress that the core of the invention lies in the product derived from a specific process. They refer to the prosecution history and statements made by the appellants to support their argument, emphasizing the product’s dependence on the claimed process.
  7. Defendants argue that since their process of oxidation of maltodextrins differs from the one claimed in the suit patent, there is no infringement. They emphasize that infringement determination should be based on the specifics of the claimed process.
  8. Defendants question the appellants’ entitlement to injunctive relief, citing instances of prosecution history estoppel. They argue that the appellants have, on multiple occasions, conceded the nature of the patent as a product-by-process, undermining their claims.


In rendering its decision on the appeal, the court conducted a meticulous and detailed examination of the impugned order, thoroughly addressing each contention put forth by the parties involved. The court asserted unequivocally that the legal stance articulated by the learned Single Judge suffered from evident and manifest legal flaws, thereby necessitating intervention through the appellate process. A critical aspect highlighted by the court pertained to the errors present in the impugned order, particularly concerning the differentiation between a “product by process claim” and a “pure product claim.” The court critiqued the Single Judge’s perspective, emphasizing that product-by-process claims extend beyond products obtained through specific process features, especially when the nature of the product resists clear definition without the inclusion of process terms.

The nature of product-by-process claims was expounded upon, emphasizing that such claims straddle the boundaries between products and process patents. These claims, according to the court’s analysis, are inherently directed towards novel and inventive products, necessitating reliance on process features for a comprehensive description. The court underscored the inappropriateness of applying different tests of novelty and standards of claim construction during grant and infringement stages, highlighting the potential for unjust outcomes.

Section 48 of the Patents Act, focusing on 48(a) and 48(b), was a focal point of the court’s analysis. The court clarified that the use of “obtained directly by that process” in 48(b) implies a distinction in the scope of protection for process claims. The interpretation of the “obtainable by” language in the FCM patent’s claim was scrutinized, with the court asserting that it extends to product claims per se, contingent on the product being both novel and inventive. The court emphasized that as long as a product-by-process claim pertains to a novel and inventive product unknown in the prior art, it falls within the ambit of Section 48(a). Rejecting the notion of limiting such claims under Section 48(b), the court stressed that the assessment of novelty should disregard process terms.

Referring to established guidelines and legal precedents, the court underscored that novelty assessment should focus on the product itself, irrespective of the manufacturing process. The court rejected the notion that a product is rendered novel solely by virtue of being produced by a new process Characterizing a product-by-process claim as an amalgam straddling the recognized distinction between products and process patents, the court portrayed these patents as founded on claims related to novel products, explaining their unique attributes through the associated manufacturing process. The court ultimately set aside the judgment, allowing the appeals and pointing out the Single Judge’s errors in appreciating the scope of product-by-process claims and the application of distinct principles in infringement actions.


The court underscores key principles related to product-by-process claims. It highlights their unique nature, straddling the product-process patent divide, and rejects the rigid notion that products must be solely described by composition. Emphasizing global acceptance, the court asserts that product-by-process claims are rooted in novel products, independent of process novelty. It advocates for consistent criteria in patentability and infringement analysis, rejecting the idea that process features limit claims during infringement. The court clarifies the distinction between Sections 48(a) and 48(b), opposing the Abbott rule and affirming challenges to product patentability irrespective of process terms. It concludes that product-by-process claims should be evaluated based on the novelty of the product, allowing them to fall under Section 48(a). The appeals are allowed, setting aside the impugned judgment, and the court permits further proceedings in the pending suits.