In a potentially favourable judgement for the Indian generics drug industry, the Delhi High Court ruled that patents are subject to cancellation (invalidation) even after they expire. The court also clarified that the patent holder retains the right to claim damages for infringement that occurred during the patent’s life.
“A revocation petition would be maintainable, and would continue to survive, even after the patent of which revocation is sought expires by efflux of time. A revocation petition can be instituted even after a Section 107 invalidity defence is taken in the infringement suit,” the order said.
Revocation vs. Invalidity
Experts said the ruling would enable pharma companies to pursue cases asking for patent cancellations even if the patents have expired. “The ruling follows that if the patent was invalid then its validity can be brought into question even after it has expired. This is a very balanced principle that considers the rights of both the patent owners and the generics industry,” said Pravin Anand, managing partner at Anand & Anand.
The dispute involves a patent for the diabetes drug Linagliptin for which Germany-based Boehringer Ingelheim Pharma was granted a patent in October 2022 with a priority date of August 2002. In February 2022, Mumbai-based Macleods Pharmaceuticals filed a petition to cancel its patent under Section 64(1) of the Patents Act 1970. Two days later, Boehringer filed an infringement suit against Macleods in the High Court of Himachal Pradesh alleging patent infringement.
Subsequently, Boehringer filed an application seeking dismissal of Macleods’ patent cancellation petition on the ground that it was filed 12 years after the patent grant. The Delhi HC quashed this application, citing that there is no prescribed time limit to file a revocation petition.
Retrospective Immunity
Since the said patent expired in August 2023, Boehringer later argued that the cancellation petition was not sustainable and should be dismissed.