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In Zydus Lifesciences Ltd. v. E.R. Squibb and Sons LLC & Ors. (FAO(OS) (COMM) 120/2025, CM APPL. 44383/2025, CM APPL. 44386/2025 & CM APPL. 44388/2025), the Division Bench of the Delhi High Court modified the interim order passed by the Single Judge, who had restrained Zydus from manufacturing, using, offering for sale, selling or importing its biosimilar version of the cancer immunotherapy drug Nivolumab in India. In doing so, the Division Bench placed particular emphasis on public interest, especially in the context of a life-saving drug.
Product-to-claim Mapping
E.R. Squibb had instituted a quia timet action to restrain the anticipated launch of Zydus’ product, ZRC-3276, prior to the expiry of the suit patent in May 2026. The patent in issue, IN 340060, titled “Human Monoclonal Antibodies to Programmed Death 1 (PD-1) for use in treating Cancer”, covers antibody 5C4, or Nivolumab, marketed outside India as Opdivo and in India as Opdyta. By order dated July 18, 2025, the Single Judge granted an interim injunction restraining Zydus from manufacturing or launching ZRC-3276. Zydus challenged that order before the Division Bench.
The Division Bench vacated the injunction. A central reason for doing so was its view that the Single Judge had granted interim relief without undertaking a proper product-to-claim infringement analysis. In patent law, infringement must be assessed by comparing the allegedly infringing product with the claims of the suit patent. The Bench found that this exercise had not been adequately carried out.
The suit patent claimed an isolated monoclonal antibody identified through two principal indicia: first, that the antibody “binds specifically to human Programmed Death (PD-1)”; and second, that it comprises chains consisting of amino acid sequences set out in the claims. The Division Bench accepted Zydus’ submission that, in the absence of a commercial launch of ZRC-3276 because of the interim restraint itself, infringement could not be inferred merely by comparing the suit patent with Squibb’s own marketed Nivolumab product. The Single Judge’s approach, which effectively proceeded on a product-to-product comparison, was therefore held to be legally untenable. The correct inquiry, the Division Bench held, was whether Zydus’ product could be mapped onto the asserted patent claims.
The Bench also gave weight to Squibb’s own statements made during prosecution regarding the scope of the word “specifically”. Squibb had then explained the claim as covering antibodies that did not show statistically significant binding to other proteins in the CD-28 family, with p < 0.05 treated as the marker of such significance. Against that backdrop, the Division Bench found it noteworthy that Zydus’ material showed binding at p < 0.0001, and held that the Single Judge had not sufficiently dealt with a submission that was central to the prima facie infringement inquiry.
More broadly, the Division Bench clarified the standard for interim injunctions in patent infringement actions under Section 48 of the Patents Act, 1970. Where a patentee establishes clear product-to-claim mapping and there is no credible challenge to validity, interim protection may readily follow. However, where such mapping is absent and the dispute raises serious and triable technical issues, restraint at the interim stage requires correspondingly stronger and more conclusive material. In such cases, particularly where the dispute concerns a life-saving drug, courts must remain alive to public interest and may adopt alternative measures to safeguard the patentee’s rights.
Public Interest
That consideration proved decisive here. The Division Bench noted that Zydus’ product was presented as an affordable biosimilar of a life-saving cancer therapy, and that Squibb’s patent was due to expire in May 2026. In those circumstances, the court considered public interest to be a weighty and indeed pre-eminent factor. It reasoned that preventing the entry of a potentially more affordable biosimilar, only months before patent expiry, could result in disproportionate harm to patients and the public at large.
The court therefore modified the Single Judge’s order by vacating the injunction, while directing Zydus to maintain and file audited accounts of the revenue generated from sales of its Nivolumab biosimilar during the subsistence of the suit patent. This, the court held, would adequately protect Squibb’s monetary interests while permitting Zydus’ market entry.
Significance of the ruling
The ruling (delivered on January 12, 2026) is significant on two counts. First, it reaffirms that patent infringement analysis must rest on a disciplined product-to-claim comparison, rather than a broader product-to-product equivalence exercise. Second, it underscores that public interest remains a vital factor in assessing interim relief, particularly where the product is a life-saving drug, the patent is nearing expiry, and an injunction may delay access to a more affordable treatment option.
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