Onus to prove invalidity of patent lies on infringer: Delhi High Court

The Delhi High Court recently observed that when an infringer seeks to defend patent infringement on the ground that the patent is invalid, the onus to prove the invalidity lies heavily on them and this standard has to be met when applying the principle of “credibility” [Novartis AG and Anr v Natco Pharma Limited]..The observation came from Justice C Hari Shankar as he restrained Natco Pharma Limited from importing, selling, offering for sale, exporting, or dealing directly or indirectly in Active Pharmaceutical Ingredient (API) containing Eltrombopag Olamine (EO). .EO is a compound which helps in enhancing platelet production and is particularly used in the treatment of thrombocytopenia (low blood platelet count).The suit patent for EO was reckoned from May 21, 2003, and the patent would remain alive for 20 years. The invention was granted non-proprietary United States Adopted Name (USAN) “Eltrombopag Olamine” and it is marketed by Novartis under the tradename “REVOLADE”.The patent is owned by Novartis. The Court was told that Natco Pharma was launching their branded EO in the market. This, Novartis argued, infringed Claim 1 of the suit patent (which is still alive) since Natco Pharma has not obtained any license from them..After hearing the arguments, the Court said that prima facie there appeared to be a fundamental misconception relating to the concepts of a “credible challenge” and “vulnerability” as the submission advanced by the defendants were predicated on the premise that the slightest shadow of doubt, which could be cast on the suit patent, was sufficient to constitute a credible challenge, therefore exposing its vulnerability to revocation. This proposition, the Court said, is completely misconceived.“Repeated attempts were made to convince me that any and every ground that the defendant sought to raise, and for which a cast iron response from the plaintiff was not immediately forthcoming, was sufficient to establish vulnerability of the suit patent to revocation. Revocation is a drastic act, and a patent, once granted, cannot be treated as easily vulnerable to revocation,” Justice Shankar noted in his judgment..He added that even if a prima facie ground is made for revocation of a patent, this is not automatic but remains to be a matter of discretion of the patent authority.“The grant of such discretion is itself a pointer to the legislative intent that, before revoking a patent, the authority is required to satisfy itself, that, all considerations having been mould in mind, revocation is absolutely necessary. Vulnerability to revocation has also to be judged on the same standard. It is only when, judged on that standard, a credible challenge to the validity of the patent as vulnerable to revocation is made out, that an infringer can escape the consequences of infringement. The standard is, therefore, high, rather than low,” the judgment said..Dealing with the facts of the present case, the Court said that the infringer never chose to challenge the suit patent either at pre-grant or post-grant stage, and therefore they have not “cleared the way” before exploiting the suit patent.“It is only when they have been “caught in the act”, as it were, that the infringer defendants, unable to dispute the charge of infringement on facts, seek to question the validity of the suit patent… In such circumstances, the holder of the suit patent would ordinarily be entitled to an injunction against continued infringement. Absent any prima facie case of vulnerability of the suit patent to revocation on the ground of invalidity, therefore, injunction cannot be refused, once infringement is established,” the Court concluded..Advocates Hemant Singh, Mamta Jha, Ankit Arvind and Mamta Bhadu appeared for Novartis. Natco Pharma was represented by advocates J Sai Deepak, Guruswamy Nataraj, Avinash K Sharma, R Abhishek and Ankur Vyas..[Read Judgment]