Zydus Lifesciences Limited Vs. E. R. Squibb and Sons

In this patent infringement appeal, respondents E.R. Squibb filed a quia timet suit anticipating that appellant Zydus' anti-cancer drug ZRC 3276 would infringe their patented monoclonal antibody (Nivolumab/Opdivo/5C4) which binds specifically to human PD-1 for treating various carcinomas, and the Single Judge granted interim injunction without product-to-claim mapping, relying on product-to-product comparison and interpreting "specifically binds" as not requiring exclusive binding. The Division Bench reasoned that the Single Judge erred in not requiring product-claim mapping as mandated under Delhi High Court Patent Rules (absent only if impossible, but needing overwhelming evidence), misinterpreted "specifically" contrary to respondents' own pre-grant clarification (no statistically significant binding to other CD28 proteins with p<0.05, whereas both products showed p~0.0001), improperly used product-product mapping instead of claim mapping, and overlooked public interest in availability of the cheaper life-saving drug amid triable technical issues, with patent expiring soon on 2 May 2026. The appeal was allowed by vacating the injunction to permit ZRC 3276's market release, but directing Zydus to file audited sales accounts till patent expiry to secure respondents' interests.

- In quia timet patent infringement suits, product-to-claim mapping is essential under Rule 3(A)(ix) of Delhi High Court Rules Governing Patent Suits, 2022; its absence requires overwhelming circumstantial evidence of infringement, not assumptions. (Paras 5-8, 26.5)

- The term "specifically binds" in patent claims must be interpreted per the patentee's pre-grant responses, meaning no statistically significant cross-binding (p-value <0.05) to related proteins; evidence showing lower p-values excludes the product from claim scope. (Paras 12-14)

- Patent infringement determination requires strict product-to-claim mapping under Section 48 of Patents Act, 1970, not product-to-product comparison; the latter is fundamentally flawed. (Paras 15-15.2, 26.4)

- While granting interim injunctions in patent cases involving life-saving drugs, courts must balance IP protection with public interest under Ramnik Lal Bhutta v. State of Maharashtra, (1997) 1 SCC 134 and Raunaq International v. I.V.R. Construction Ltd., (1999) 1 SCC 492; if issues are triable, alternate remedies like accounts suffice instead of absolute restraint. (Paras 2-4, 26.5.2-26.5.10)

**Case Details**  

**Case Title** : Zydus Lifesciences Limited Vs. E. R. Squibb and Sons, LLC & Ors.  

**Order Date** : 12th January, 2026  

**Case Number** : FAO(OS) (COMM) 120/2025 (CM APPL. 44383/2025 & connected CM APPLs.)  

**Neutral Citation** : 2026:DHC:0242-DB  

**Court** : High Court of Delhi  

**Judge** : Hon’ble Mr. Justice C. Hari Shankar and Hon’ble Mr. Justice Om Prakash Shukla

[Readers are advised not to treat this as substitute for legal advise as it may contain errors in perception, interpretation, and presentation]  

[Written By: Advocate Ajay Amitabh Suman, IP Adjutor [Patent and Trademark Attorney], High Court of Delhi]