This legal article delves into the dispute brought before the Hon'ble High Court of Delhi in a patent infringement suit, where the primary issue revolves around the scope of the plaintiff's rights in a product-by-process claim. The plaintiff contended that the patent claim was a product claim, while the defendant argued that the scope of the claim was limited to the process disclosed in the patent. The court's analysis and findings in this case shed light on the significance of process features in product-by-process claims and the implications for patent protection.

Introduction:
In the subject matter suit for patent infringement before the Hon'ble High Court of Delhi, the central dispute pertained to the nature and scope of a patent claim relating to water-soluble iron carbohydrate complexes used in the formulation of a medical product known as FCM (Ferric Carboxymaltose). The plaintiff asserted that Claim 1 of the patent was a product claim, while the defendant contended that it was a product-by-process claim, limiting the plaintiff's rights to the specific process disclosed in the patent.

Product-by-Process Claims:
A product-by-process claim is a type of patent claim that defines a product based on the process by which it is made rather than its structural features. These claims are frequently used when the product itself cannot be fully described or characterized by its physical properties alone, and the process used to create it is essential to its unique properties. In such cases, the patent claim may specify the process steps required to manufacture the product, making it necessary for any potential infringer to use the same process to be liable for infringement.

Court's Analysis and Findings:
The Hon'ble High Court of Delhi analyzed the language of Claim 1 of the patent (IN'221536) and reviewed the complete specification and prosecution history to determine the scope of the claim. The court observed that the patent itself admitted that iron carbohydrate complexes were already known, and the invention's novelty lay in using maltodextrin as the starting material and oxidizing it with an aqueous hypochlorite solution to produce FCM.

Prosecution History Estoppel:
The principle of prosecution history estoppel holds that a patentee cannot make inconsistent statements during the patent application process, claiming certain properties are solely due to the process, and later assert broader claims that encompass other processes or products. In this case, the plaintiff's admission regarding the significance of the process features in obtaining the unique properties of FCM led the court to limit the scope of the claim accordingly.

The Defendant's submission in February 2020, opposing a third party's patent application (No. 3474/CHE/2013), further strengthens the Plaintiff's admission. In their opposition, the Plaintiff mentioned at multiple instances that Claim 1 of IN'536 relates to a process claim.

The Court, while evaluating infringement in a process by product patent, focuses on the process as a limiting factor. Typically, infringement is deemed to occur only when a product is made using the same process as claimed in the patent. Consequently, if the Defendants can successfully demonstrate that their product FCM is manufactured using a different process, they cannot be accused of infringement.

Analyzing Claim-1 in IN'536, it becomes evident that the claim covers water-soluble iron carbohydrate complexes obtained from an aqueous solution of iron (III) salt and an aqueous solution of the oxidation product of one or more maltodextrins using an aqueous hypochlorite solution at an alkaline pH. On the other hand, the Defendants' process for obtaining FCM involves using hydrolyzed starch treated with an appropriate acid medium in an acidic pH, followed by heating to create a mixture of hydrolyzed starch.

Based on this analysis, the Court observed that, at a prima facie stage, the Defendants have successfully established that their process for obtaining FCM falls outside the scope of IN'536. As a result, the Court held that the impugned process of CRPL and VBPL (Defendants) is non-infringing.

Plaintiff' Reliance on interim order passed in different Suit is merely persuasive:
The Plaintiff argued that various interim orders issued by different Courts regarding FCM demonstrated the strength of IN'536. They urged the Court to maintain uniformity in judicial decisions by granting an injunction against the Defendants. However, this argument was not accepted by the Court, being merely persuasive in nature.

Conclusion:
The case before the Hon'ble High Court of Delhi highlights the importance of product-by-process claims in patent law. Patent protection secured through such claims is limited by the process used to create the product, and a monopoly cannot be claimed over the product as a whole. The court's analysis and findings provide valuable insights into the scope of product-by-process claims and the significance of prosecution history estoppel in determining patent infringement case.

Case Law Discussed:
Case Title: Vifor International Limited Vs MSN Laboratories Limited
Date of Judgement:24.07.2023
Case No.CS Comm 261 of 2022
Neutral Citation:2023:DHC:5222
Name of Hon'ble Court:High Court of Delhi
Name of Hon'ble Judge:Jyoti Singh, H.J.

Disclaimer:
Information contained herein is being shared in the public Interest. The same should not be treated as substitute for legal advice as it is subject to my subjectivity and may contain human errors in perception, interpretation and presentation of the facts and law involved herein.

Written By: Advocate Ajay Amitabh Suman, IP Adjutor - Patent and Trademark Attorney
Email: [email protected], Ph no: 9990389539