A patent claim typically consists of three parts: (i) the preamble, (ii) the transitional phrase, and (iii) the body. The preamble identifies the category of the invention and sometimes its purpose (e.g., “A box for packaging” or “A process for manufacturing a box for packaging”). The body sets out the specific features and limitations of the invention, defining the boundaries of protection. Connecting these two is the transitional phrase, most commonly, “comprising,” “including,” “consisting of,” or “consisting essentially of.”
Transitional phrases receive relatively less attention during drafting and prosecution, but they have significant legal implications. The Delhi High Court’s ruling in Frimline Private Limited & Anr. v. K-Smatco Lifesciences Private Limited & Ors. (CS(COMM) 808/2025, decided on 29 August 2025) highlights the importance of the term “comprising” in determining the scope of protection afforded to a patent.
Background
The dispute arose in connection with Indian Patent No. 382949, titled “A Pharmaceutical Composition for Anaemia” (“the patent”). The patent discloses a pharmaceutical composition comprising a synergistic combination of Lactoferrin and Guanosine Nucleotide or its salts for the treatment of iron deficiency anaemia, anaemia of inflammation, and neuro-degenerative disorders.
Frimline had been commercialising products under the brands “FERRONEMIA,” “FERRONOMIC,” and related derivatives since 2018. In July 2025, Frimline discovered that the defendants were marketing FERROTOK PLUS, which allegedly contained the same combination of active ingredients, and thus, infringed the patent.
The central controversy was whether the defendants’ product, which contained Disodium Guanosine 5-Monophosphate (“DGMP”), was covered by the suit patent. Notably, DGMP was not expressly listed in claim 1 or claim 2 of the patent. Here, it is useful to consider the two claims in question, as below.
Claim 1 recites:
“A pharmaceutical composition comprising a combination of:
- a) Lactoferrin; and
- b) one or more Guanosine Nucleotide or a pharmaceutically acceptable salt thereof;
wherein an amount of the Lactoferrin ranges from 5 to 90% by wt. of the composition.”
Claim 2 specifies that the Guanosine Nucleotide may be selected from Guanosine monophosphate (GMP), Guanosine diphosphate (GDP), Guanosine triphosphate (GTP), or combinations thereof.
Analysis
The Court observed that claim 1 of the patent used the phrase “comprising” that gives broader protection and permits the inclusion of variants and salts of the recited compounds. The Court relied upon the Division Bench’s observations in F. Hoffmann-La Roche Ltd. & Anr. v. Cipla Ltd. (2015 SCC OnLine Del 13619), which had recognised that “comprising” is enabling and non-restrictive. Reference was also made to Terrell on the Law of Patents (19th ed.), which clarifies that “comprising” does not equate to “consisting only of.”
The Court also emphasised that patent claims must not be read in isolation but in conjunction with the complete specification, following Biswanath Prasad Radhey Shyam vs Hindustan Metal Industries ((1979) 2 SCC 511). In the present case, a review of the “Detailed Description of the Invention” revealed that DGMP was expressly mentioned as one of the contemplated embodiments of the invention, and one of the examples of the specification also described a specific formulation containing DGMP.
Decision
Based on the claim language and the disclosure in the specification, the Court concluded that DGMP is covered in the Suit Patent. By mapping the elements of the defendants’ product against the claims of the suit patent, the Court found that the plaintiffs had made out a strong prima facie case of infringement. Consequently, the Court granted an interim injunction restraining the defendants from manufacturing, marketing, distributing, or otherwise commercialising any infringing product during the life of the suit patent.
Conclusion
The Frimline ruling is a reminder of the significance of transitional phrases in patent claims, and that they cannot be lightly dismissed. Here, the word “comprising” came to the patentee’s rescue, granting a broader scope of protection, and encompassing variations disclosed in the specification but not specifically claimed in the claims.
For patent practitioners, two lessons are on offer: First, the choice of transitional phrases during claim drafting can directly impact the breadth of protection. Second, during prosecution, when patent offices propose amendments narrowing “comprising” to restrictive terms like “consisting of” or “consisting essentially of,” applicants and agents should exercise particular caution, as such changes may unintentionally end up limiting rights.
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