Introduction:

In E.R. Squibb and Sons LLC & Ors. v. Zydus Lifesciences Limited (2025 LiveLaw (Del) 825), the Delhi High Court issued an interim injunction restraining Zydus Lifesciences Limited, a prominent Indian pharmaceutical company, from manufacturing, selling, importing, exporting, or otherwise dealing with any biologic that is similar to Nivolumab—marketed globally as “Opdivo®”—while the patent is in force. The suit patentees, led by E.R. Squibb and Sons LLC, hold a patent titled “Human Monoclonal Antibodies to Programmed Death 1 (PD‑1) for use in treating Cancer,” valid from May 2, 2006, to May 2, 2026. Squibb initiated legal proceedings after discovering that Zydus had registered a clinical trial for its biosimilar candidate ZRC‑3276, citing Nivolumab (Opdivo®) as the reference product. This led Squibb to apprehend that Zydus intended to launch its biosimilar in India before the patent term expired, prompting them to seek an injunction. The Court, presided over by Justice Mini Pushkarna, granted interim relief to Squibb, noting that any launching, manufacturing, or stockpiling of the infringing product during the patent term would undermine their statutory monopoly and compromise public interest in innovation.

Arguments of the Plaintiffs (E.R. Squibb and Sons LLC):

• Infringement via Clinical Trial Registration:

Squibb asserted that Zydus’s clinical trial application for ZRC‑3276, which explicitly referenced Nivolumab (Opdivo®), amounted to a clear indication of intent to replicate the patented biologic. This, they contended, constituted at least preparatory acts toward infringement, justifying immediate judicial intervention to prevent any further manufacturing or distribution efforts.

• Valid Patent with Time-Bound Monopoly:

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.

• Global Patent Recognition and Opposition Failures:

The plaintiffs underscored that the patent had been successfully sustained in thirty out of fifty jurisdictions where validity was challenged. Furthermore, Zydus’s post-grant opposition in India remained unresolved, but had not yet met the burden to overthrow patent validity.

• Stockpiling Constitutes Infringement:

Squibb argued that producing, offering for sale, or stockpiling a patented biologic during the patent life constitutes infringement—even if the product is not immediately released into the market. The domestic statute, they asserted, does not permit a “launch-ready buffer” to circumvent patent controls.

• Necessity for Interim Relief:

They maintained that, without interim relief, Zydus could cause irreparable harm by undermining Squibb’s market exclusivity and commercial prospects. The balance of convenience, Squibb contended, favored granting an injunction to protect its statutory rights and preserve the integrity of the patent regime.

Arguments of the Defendant (Zydus Lifesciences Limited):

• Requirement of Formal Patent Challenge:

Zydus contended that no patent invalidity had been established via a final adjudication; the post-grant opposition was pending, and they reserved the right to challenge the patent fully. They argued that a mere reference to the reference product in a trial registration did not equate to infringement and that they had a right to conduct legitimate trials.

• Permissibility of Clinical Trials:

Zydus asserted that clinical trials fall under “experimental use” exemptions and are integral to the public interest in accessing medicines. They suggested that trials conducted prior to patent expiry to gather safety and efficacy data should be permissible and distinguished from acts of commercial distribution.

• Public Interest in Biosimilars:

Zydus emphasized the importance of biosimilars, like Nivolumab, in enhancing access to lifesaving biologic therapies. They argued that barring clinical research activities up to launch date would delay the entry of cost-effective treatments into the Indian healthcare system.

• Allegation of Preemptive Lawsuit:

Zydus framed the suit as preemptive and aggressive, aimed at chilling legitimate scientific inquiry and swift introduction of biosimilars. They asserted that the patent’s 2026 expiry date provided a lawful cut-off; consequently, any pre-launch notice by Squibb was unnecessary and obstructive.

• Limited Interim Relief Justification:

Finally, Zydus objected to the interim injunction, maintaining that Squibb had not demonstrated urgency or demonstrated magnitude of irreparable harm. They argued that financial uncertainty for cancer patients and market competition warranted denial of interim restraint, pending invalidation or expiry of the patent.

Court’s Judgment and Reasoning:

Justice Pushkarna, after reviewing the materials and hearing detailed arguments, issued a carefully reasoned interim order with key conclusions:

• Patent Validity Presumed Until Proven Otherwise:

The Court reiterated that courts must presume patent validity until conclusively overturned. Zydus’s post-grant opposition was pending, and there was no evidence of successful invalidation. Patent enforcement should not be deferred until after expiry where prima facie infringement arises.

• Clinical Trial Referencing as Clear Indicator of Intent:

Justice Pushkarna held that by officially registering ZRC‑3276 with explicit reference to Nivolumab (Opdivo®), Zydus revealed intent to develop a biosimilar that would enter the market during the patent term. Such acts, the Court held, are more than exploratory—they signal concrete steps toward commercialization.

• Stockpiling and Manufacturing Constitute Infringement:

The Court stressed that the manufacture of the biologic, even before market launch, infringes the patentee’s exclusive manufacturing and distribution rights under Section 48 of the Patents Act. Preparing stock or commercial quantities during the pendency of the patent would cause immediate harm.

• Balancing Public Interest and Innovation Incentives:

While recognizing the public interest in biosimilars, the bench concluded that this interest does not justify undermining statutory IP rights. The Court observed that post-patent expiry, Zydus could lawfully launch; meanwhile, granting interim protection to Squibb maintained the integrity of the patent system.

• Urgency and Hardship to Plaintiffs:

Justice Pushkarna noted that Squibb would suffer irreparable harm if Zydus launched before expiry, losing market share with no remedy. The balance of convenience tipped in Squibb’s favor, mandating interim protection.

• Affidavit Disclosure Requirement:

The Court directed Zydus to file an affidavit within four weeks, detailing the quantities of ZRC‑3276 biosimilar manufactured to date. This would enable monitoring of potential future infringement or stockpiling.

• Time-Bound Protection:

The injunction was ordered to last until patent expiry on May 2, 2026. Post-expiry, Zydus is free to launch or market its biosimilar, safeguarding Squibb’s rights while preserving future market competition.