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
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.
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
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
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.
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 Law Discussed:
Case Title: Vifor International Limited Vs MSN Laboratories Limited
Date of Judgement:24.07.2023
Case No.CS Comm 261 of 2022
Name of Hon'ble Court:High Court of Delhi
Name of Hon'ble Judge:Jyoti Singh, H.J.
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
Email: [email protected]
, Ph no: 9990389539