Delhi HC Clears Zydus' Cancer Drug ZRC-3276 Despite BMS Patent Claim

Earlier, the Medical Dialogues Team had reported that the Delhi High Court had restrained Zydus Lifescience from launching its proposed biosimilar of the cancer immunotherapy drug Nivolumab until May 2, 2026, the date on which the suit patent expires. The court's order came as part of an interim injunction in favor of global pharmaceutical major Bristol Myers Squibb (BMS) and its affiliates, who claimed that Zydus's biosimilar infringed their valid and subsisting Indian Patent No. IN 340060.

The dispute arose from a patent infringement suit filed by E.R. Squibb and Sons LLC and other Bristol Myers Squibb group entities, holders of Indian Patent No. IN 340060, which covers the monoclonal antibody Nivolumab, marketed globally as Opdivo® and in India as Opdyta®. Bristol Myers Squibb alleged that Zydus Lifesciences’ proposed product ZRC-3276 infringed its patent and sought a quia timet injunction to restrain its manufacture and sale even before commercial launch.

The impugned single-judge order accepted this plea and barred Zydus Lifesciences from releasing its product, leading the Ahmedabad-based company to approach the division bench in appeal.

The court devoted significant attention to explaining the scientific foundation of the dispute. It noted that Nivolumab is an anti-PD-1 monoclonal antibody used in cancer immunotherapy. The patent claims asserted by Bristol Myers Squibb rest on two essential features: first, that the antibody “binds specifically to human Programmed Death-1 (PD-1)”, and second, that it contains specific amino-acid sequences in its heavy and light chains.

Zydus Lifesciences argued that although its product was a biosimilar of Nivolumab for regulatory purposes, it did not fall within the scope of the patent claims because it did not bind exclusively to PD-1 and showed statistically significant binding with other proteins belonging to the CD-28 family.

Zydus Lifesciences’ central submission was that patent infringement under Section 48 of the Patents Act, 1970 can only be established through product-to-claim mapping, not by comparing two commercial products. The company argued that Bristol Myers Squibb had failed to map ZRC-3276 to the claims of Patent IN 340060, a requirement expressly mandated by Rule 3(A)(ix) of the Delhi High Court Patent Suits Rules, 2022.

Zydus further relied on experimental data, including independent third-party studies, showing that ZRC-3276 had a ‘p’ value of less than 0.0001 for binding with non-PD-1 receptors. According to Zydus, Bristol Myers Squibb had itself defined such binding during patent prosecution as “statistically significant,” meaning that ZRC-3276 fell outside the scope of the patent and merely followed prior art.

Zydus also underscored the public interest dimension, stating that treatment using ZRC-3276 would be around 70% cheaper than therapy using Bristol Myers Squibb’s patented drug, potentially expanding access to immunotherapy for cancer patients across India.

Bristol Myers Squibb contended that ZRC-3276 was admittedly a biosimilar of Nivolumab and therefore necessarily shared the same amino-acid sequence and functional properties as the patented antibody. The company argued that the expression “binds specifically to PD-1” did not require exclusive binding and that some cross-reactivity with other CD-28 family receptors would not take Zydus’ product outside the patent claims.

Bristol Myers Squibb further maintained that since the suit was a quia timet action and ZRC-3276 had not yet been commercially launched due to the interim restraint, strict product-to-claim mapping was impracticable. According to the company, the court was entitled to rely on indirect evidence, regulatory filings, and biosimilarity claims to arrive at a prima facie finding of infringement.

The division bench, however, sharply disagreed with the approach adopted by the single judge. It noted that the injunction had been granted without any product-to-claim mapping whatsoever, a lapse the court found legally untenable.

“This case… is peculiar, as there is admittedly no mapping of the appellant’s product ZRC-3276 onto the claims in the respondent’s suit patent at any stage. Injunction has, therefore, been granted without any product-to-claim mapping,” the court observed.

The bench rejected reliance on product-to-product comparison, reiterating that patent infringement must be determined by comparing the allegedly infringing product with the patent claims, not with the patentee’s own marketed drug.

The court also found fault with Bristol Myers Squibb’s interpretation of the word “specifically,” pointing out that during prosecution proceedings the company itself had equated “specific” binding with absence of statistically significant binding to other CD-28 family proteins.

“The respondent has itself… explained the expression ‘specifically’ as meaning that there should be no statistically significant binding with other proteins of the CD-28 family,” the judgment recorded.

A central theme of the judgment was public interest. While recognising that patent rights deserve protection, the court emphasised that life-saving drugs cannot be kept out of the market on the basis of inconclusive or debatable technical material.

“Courts owe a debt to society… while deciding whether to grant, or not to grant, an absolute interlocutory injunction,” the bench stated, warning that cancer patients could not be deprived of affordable therapy on tenuous grounds.

The court also noted that the patent for Nivolumab is set to expire on 2 May 2026, leaving only a few months of remaining exclusivity.

Allowing the appeal, the Delhi High Court modified the impugned order and vacated the injunction restraining Zydus Lifesciences. It held that the dispute involved highly technical and triable issues requiring expert evidence and did not justify a complete market ban on a cancer drug.

The court ruled:

“Where the issue is triable, or involves complicated technical issues which would appropriately need a trial, then, in our opinion, where the product in question is a life-saving drug, the Court has to err in favour of public interest”

Instead of restraining sales, the bench directed Zydus Lifesciences Limited to maintain and periodically file audited accounts of revenues earned from ZRC-3276 until expiry of the patent, thereby safeguarding Bristol Myers Squibb’s financial interests if it ultimately succeeds in the suit.

With this ruling, the Delhi High Court has reaffirmed that patent enforcement must be grounded in strict claim analysis and balanced against public interest, especially where access to essential medicines and patient lives are at stake.

To view the official order, click the link below: