Introduction
In a recent development for biologics patents in India, the Delhi High Court has granted interim relief to E.R. Squibb in their infringement suit1 against Zydus Lifesciences. The suit concerns IN 340060, which claims the monoclonal antibody Nivolumab—commercially known as Opdivo®—used in immunotherapy for various cancers.
On July 18, 2025, the Court restrained Zydus from launching its proposed biosimilar of Nivolumab (identified as ZRC-3276) during the subsistence of IN 340060, which expires on May 2, 2026. The injunction, granted even before commercial launch, highlights the Court’s willingness to intervene even at the interim stage when there is sufficient evidence of intent to infringe.
This blog analyses the background of the dispute, key arguments, and legal reasoning that led to the grant of interim relief.
Background
The Plaintiffs initiated proceedings after discovering in April 2022 that the Defendant had sought clinical trial approval for a biosimilar version of Nivolumab. Further investigation revealed that the Defendant had registered a clinical trial for its biosimilar candidate, ZRC-3276, with the Clinical Trial Registry of India (CTRI), identifying Opdivo® as the reference product.
In September 2022, Zydus received permission from the Central Drugs Standard Control Organisation (CDSCO) to manufacture and import ZRC-3276 for clinical trials under the New Drugs and Clinical Trials Rules, 2019. Plaintiffs also discovered that Zydus had applied for regulatory marketing approval, suggesting that commercial launch was imminent.
Importantly, Zydus Healthcare Ltd., a group company of the Defendant, had filed a post-grant opposition against the suit patent and responded to a cease-and-desist letter from the Plaintiffs in May 2022, thereby demonstrating knowledge of the patent.
Given the imminent threat of market entry, the Plaintiffs filed a quia timet action seeking an injunction to prevent infringement.
Plaintiff’s Contentions
Squibb highlighted that their patent, granted after fourteen years of prosecution, was valid and enforceable under the Indian Patents Act. With the term set to expire on May 2, 2026, Squibb emphasized that any premature entry into the market by Zydus would devalue their limited period of exclusivity and defeat the incentive-oriented design of patent laws.
Sequence Identifier ID (“SEQ ID”) defined by Opdivo®/Opdyta® (Nivolumab) was mapped, including the six CDR sequences in figure 4A and figure 4B of suit patent and SEQ 4 and SEQ 11 with that of the International Non-Proprietary Name (“INN”). Accordingly, it was contended that the defendant can claim its product to be bio-similar to Nivolumab only if the said bio-similar version has six CDR sequences of Claim 1, or the VH/VL region amino acid sequence of Claim 3.
Since no commercial product of the defendant existed against which claims could be mapped, claims were mapped against the Nivolumab INN, which was used as a reference product by the defendant for development of its bio-similar product, ZRC-3276. Nivolumab INN was found to be mapping onto Claims 1 and 3 of the suit patent. Therefore, the Plaintiffs contended that any reference to Nivolumab by the defendant would constitute infringement of the suit patent.
Finally, Squibb asserted that without interim relief, Zydus could cause severe harm by damaging the Squibb’s market exclusivity and commercial prospects; therefore, injunction should be granted to protect its statutory rights and preserve the integrity of the patent regime.
Defendant’s Arguments
Zydus denied infringement and argued that its product binds not only to PD-1 like the suit patent, but also to other members of the CD-28 receptor family, taking it outside the scope of the patent claims.
Zydus asserted that their product, ZRC-3276, is bio-similar to plaintiffs’ Nivolumab. However, bio-similarity by itself does not substantiate infringement as it is based upon product-to-product comparison, whereas, infringement requires claim to product mapping.
Zydus also asserted that the exercise of mapping undertaken by the plaintiffs focusses to Nivolumab. However, the term “Nivolumab” is assigned by the WHO, and the term cannot be exclusive to any one entity. As per WHO’s description for Nivolumab, even non-isolated antibodies that do not bind specifically to PD-1 can be termed as “Nivolumab”, as long as they have the sequences as mentioned in the WHO drug information document.
Further, the Defendant challenged the validity of the suit patent on grounds of lack of novelty, inventive step, and non-patentability. It submitted in-house experimental data, along with an independent report from Sardar Patel University, allegedly showing the binding affinity of the defendant’s product to other members of the CD-28 family.
Court’s Analysis
The Court rejected the Defendant’s arguments at the interim stage and found a strong prima facie case in favour of the Plaintiffs.
It was held that none of the prior art cited by the Defendant disclosed the specific amino acid sequences and CDRs of the 5C4 antibody (“Nivolumab”) claimed in the suit patent. It also reaffirmed that biosimilarity, as determined by regulatory agencies, is distinct from patent infringement, which is a question of whether the product falls within the scope of the claims.
Considering the test results filed by the defendant, it was held apparent that both the products, i.e., Opdivo® of the plaintiffs and ZRC-3276 of the defendant, fall within the scope of the claims of the suit patent. The experiments and the technical reports of the defendant demonstrated that defendant’s product, ZRC-3276 is a bio-similar of the plaintiff’ product, Opdivo®thus, . Thus, on account of being bio-similar, ZRC-3276 was held to have the same claimed sequences of the suit patent, which is admittedly Nivolumab.
As to the binding argument, the Court clarified that non-substantial binding cannot be equated to no binding at all. Therefore, the test results of the defendant – that show plaintiff’s product substantially does not bind to CD-28 – cannot be construed to mean that there exists no binding with the CD-28 receptors. Therefore, to say that the suit patent exclusively binds to PD-1, was held to be prima facie incorrect.
The Court also noted that plaintiffs run an affordable scheme for patients in India, being Patient Assistant Programme (“PAP”). Public interest in continued access to Nivolumab under the PAP and the Plaintiffs’ submission that pricing in India is already at the lower end of the global scale was duly noted.
In view of the above, the Court restrained the defendants and all others acting on its behalf from manufacturing, using, selling, offering for sale, importing, exporting, advertising or dealing in any bio-similar/similar biologic of Nivolumab, the suit patent, during the pendency of the present suit. The defendant was also directed to file an affidavit disclosing the quantity of its manufactured bio-similar product
Our Analysis and Conclusion
This judgment affirms that premature entry into the market of a patented biologic, even before expiry, can attract serious legal consequences. The Court’s analysis reinforces that it is not enough for a patentee to merely hold a valid patent—there must be a clear mapping of the asserted claims to the alleged infringing product. In doing so, the judgment sets a meaningful precedent: the burden lies on the patentee to demonstrate how a biosimilar overlaps with the patented invention, even at the interim stage.
By granting injunctive relief before commercial launch, the Court strengthens the framework for biologic patent enforcement in India. It empowers patent holders to proactively restrain biosimilar launches during the term of the patent, particularly when regulatory filings and reference product disclosures indicate an imminent threat of infringement. Notably, the Court’s restraint on post-expiry commercialization of products manufactured during the patent term also signals a tougher stance on stockpiling.
The order highlights a growing judicial willingness to grant early-stage relief where there is credible evidence of infringement and intent to launch. Biosimilar manufacturers must therefore proceed with caution, while patent holders can take confidence in India’s increasingly robust and nuanced approach to biologics-related patent protection.