The Delhi High Court has cautioned that in patent infringement cases involving life-saving drugs, an interlocutory injunction should not be granted where the issues are highly technical and triable, and a clear prima facie case is not made out. The Court clarified that while product-to-claim mapping is essential to prove infringement, its absence requires “overwhelming circumstantial material” for an injunction to be granted.
Emphasising that an “indirect mapping” via a flawed bio-similarity analysis did not meet this standard, the High Court held that a patentee is bound by the representations made during the prosecution of the patent. The Court thus stated that the respondent’s own definition of “statistically significant” binding, which its own product and the appellant’s product failed to meet, weakened its prima facie case for infringement.
The Court explained that in cases concerning life-saving therapies, where withholding the product could cause irreparable prejudice to the public, courts must tilt in favour of public interest. The plaintiff’s interest can be adequately secured by alternative methods, such as directing the defendant to maintain accounts, rather than granting an absolute injunction.
Accordingly, the Court vacated the injunction granted by the Single Judge was vacated, and directed the appellant (Zydus Lifesciences) to maintain and file audited accounts of the amounts earned from the sale of the allegedly infringing product (ZRC 3276) with the Court Registry until the expiry of the suit patent on May 02, 2026.
The Division Bench comprising Justice C. Hari Shankar and Justice Om Prakash Shukla observed that the case was peculiar as the injunction was granted without any mapping of the appellant’s product onto the claims of the respondent’s suit patent. Rather, patent infringement is to be assessed on the basis of a product-to-claim mapping, and the Single Judge’s reliance on a product-to-product mapping was ‘fundamentally flawed’.
The Bench found the Single Judge’s “biosimilar analysis” to be erroneous, and explained that the premise that biosimilars must have identical amino acid sequences was not supported by the ‘Similar Biologic Guidelines’, which only mandate similarity in “quality, safety and efficacy”. The Bench also noted a contradiction in the impugned judgment, which observed that biosimilar drugs could be “chemically different” even with similar amino acid sequencing, making a finding of infringement highly arguable.
The Bench noted that the respondent, during pre-grant objections, had defined the term to mean no statistically significant binding with other proteins of the CD-28 family (p-factor < 0.05). The appellant’s product, with a ‘p’ binding factor of 0.0001, showed statistically significant binding with other proteins, a point the impugned judgment failed to address.
Lastly, the Bench cautioned that public interest is a pre-eminent consideration when granting injunctions, especially for life-saving drugs. Given the nature of the product, the imminent expiry of the patent, and the highly arguable nature of the infringement claim, the Bench found that the balance of convenience favoured allowing the product on the market while securing the respondent’s financial interests.
Briefly, the appeal was filed by Zydus Lifesciences Limited against an order that restrained it from manufacturing or releasing its anti-cancer drug, ZRC 3276. The respondent, E. R. Squibb and Sons, LLC, alleged that ZRC 3276 infringed its Indian Patent No. IN 340060 for a monoclonal antibody known as 5C4 (Nivolumab). The respondent’s patent (IN’060) is for an “isolated monoclonal antibody” used in cancer treatment. The key features of the patent claim are that the antibody (i) binds specifically to human Programmed Death (PD-1) and (ii) comprises specific amino acid sequences in its heavy and light chains. This patent is set to expire on May 02, 2026.
When the matter reached High Court, the Single Judge granted an injunction in a quia timet action (an action to prevent future harm), despite the absence of a direct product-to-claim mapping of the appellant’s product. The injunction was based on an “indirect mapping” through a “biosimilar analysis”.
The appellant argued that its product did not infringe the patent because it does not “bind specifically to PD-1” as it also binds to other proteins of the CD-28 family with statistical significance. It was submitted that during the patent prosecution, the respondent itself defined “specifically” as not having statistically significant binding with other proteins (a ‘p’ value of less than 0.05). The appellant also highlighted that its product would be 70% cheaper than the respondent’s patented drug, making it a vital public interest consideration.
Appearances:
Senior Advocates Dr. Abhishek Manu Singhvi and Dayan Krishnan, along with Advocates Adarsh Ramanujan, Bitika Sharma, Vrinda Pathak, P.S. Manjunathan, Rajnish Kumar, Aakashi Lodha, Shreedhar Kale, Parth Singh, Chanan Parwani, and Rishi Agrawala, for the Appellant
Senior Advocate Sandeep Sethi, along with Advocates Pravin Anand, Archana Shanker, Prachi Agarwal, Devinder Singh Rawat, Elisha Sinha, Manan Mondal, Krisna Gambhir, and Shreya Sethi, for the Respondent
