In a landmark case, Gilead Pharmasset, LLC v Sankalp Rehabilitation Trust and Ors., the Indian Patent Office (IPO) in Kolkata granted a patent to Gilead Pharmasset, LLC (Gilead), covering the prodrug molecule of anti-HCV drug Sofosbuvir. The IPO rejected all the 13 pre-grant oppositions, filed by various opponents including pharma companies, advocacy groups, and individuals against the patent application. The case spanned a decade.

The patent application was opposed primarily on the grounds of lack of novelty, lack of inventive step, non-patentability under section 3(d), and insufficiency of disclosure and failure to disclose information under section 8 of the Indian Patent Act, 1970. Since these multiple oppositions were filed at varying intervals, the grant proceedings were substantially delayed.

After considering all the materials on record, the Controller of Patents (Controller), held as follows:  made the following key findings:

• Validity of priority date of the application: The Opponents challenged the priority application dated March 30, 2007, based on the patent application US 60/309,915 and argued that submitted documents D23 and D24 should be considered valid prior art for assessing the novelty of the claims. However, the IPO found these arguments unpersuasive, noting that the priority document was valid and adequately disclosed the claimed compound’s components and stereochemical configurations.
• Lack of Novelty: The IPO concluded that the claimed compounds were novel due to their structural differences and lack of explicit disclosures in the cited documents, strengthening the novelty of the claimed compound and its process of preparation.
• Lack of inventive step: The IPO acknowledged the uniqueness of the claimed compound comprising specific moieties and substituents, which were not obvious compared to the cited prior art. The IPO also rejected the opponents’ arguments suggesting the compound was obvious in view of prior art disclosing HIV or cancer treatments, emphasizing that applying these teachings to HCV treatments without considering structural and stereochemical aspects would be implausible.
• Non-patentability under section 3(d): The IPO rejected the argument that the claimed invention was a mere discovery of a new form of a known substance which does not result in the enhancement of the known efficacy of the substance. It held that the opponents’ reliance on prior art failed to establish the existence of any known substance with similar structure and efficacy to the claimed compound, or that the claimed invention lacked novelty and efficacy.
• Sufficiency of disclosure: The IPO found that the invention’s description in the application extensively covers the structure, stereochemistry, and preparation methods of the claimed compounds. Furthermore, examples and procedures outlined in the description provide adequate guidance and the claimed compound’s process, enabling skilled practitioners to understand and implement them effectively.

K&S Partners’ team comprising Litigation Practice Chair, Sanjeev Kumar Tiwari, Practice Lead (Life Sciences, Chemistry & Pharma, Amrish Tiwari and Partner and Chem-Pharma Patent Expert, Dr Jyoti Choithani Ramani, successfully represented Gilead Pharmasset, LLC in this important case.