To date, the evolution of Indian patent jurisprudence has been limited to the formulation of principles for granting interim injunctions. Given the huge backlog of cases, trials can take three to four years to reach a conclusion. Therefore, it is imperative that India develops clear principles of granting interim injunctions which have objective statutory approval and are rooted in sound logic, taking into account the transience of the technology industry.

The prerequisites for the grant of an interim injunction in a patent infringement suit are: 

  • prima facie case of validity of the plaintiff’s patent. 
  • prima facie case of infringement of the plaintiff’s patent by the defendant. 
  • The threat of irreparable harm to the plaintiff in the event that an interim injunction is denied. 
  • The fact that the balance of convenience lies with the plaintiff.

These requirements are generally similar to those for the infringement of copyrights or trademarks. The primary difference between patent suits and other IP suits is the first requirement, since it must be established due to an absence of presumptive validity to a patent under Section 13(4) of the Patents Act 1970. In other words, if a patent grant is bestowed with presumptive validity under the act, the plaintiff need not establish the first requirement.

In addition to these requirements, certain other principles have evolved in patent matters, but more by way of caution than as absolute dogmas. Of these, one rule of caution that was observed for several years was the "six-year rule", whose foreign origins may be sourced to an observation made in Terrells on Patent (ninth edition). According to the book, a patentee should show undisturbed possession and enjoyment of the patent for at least six years before the controversy arose.

The Indian origins of the six-year rule may be traced to the ruling of the Madras High Court in Manicka Thevar v Star Plough Works (1965). According to this decision, the courts were required to act with a modicum of circumspection in granting interim injunctions in cases where patents in suit were less than six years old. This rule was ultimately recognised as obsolete by the Madras High Court in Mariappan v Safiullah (2008). The rule was voided since it was recognised that there was no basis for such a rule of caution in the act, and such rule acted to the detriment of innovators/patentees.

As this rule was made obsolete, it is surprising that the same rule was rephrased as the "recent patent rule" and applied in other cases. Most notably, the Calcutta High Court in Hindustan Lever v Godrej Soaps (1996) postulated that when the patent sought to be enforced is a recent one, an interlocutory injunction should not be granted. This rule was applied again by the Bombay High Court in Novartis Ag v Mehar Pharma (2004), and continues to be invoked and applied.

Refreshingly, the Bombay High Court diverged from this trend in Novartis Ag v Adarsh Pharma (2004), in which it pronounced that nowhere in the Hindustan decision did the Calcutta High Court state that an interim injunction must never be granted where the patent is of recent origin.

Not only is the word “recent” vague, but the application of such a rule militates against Section 11A(7) of the act, which safeguards the rights of “recent” patent holders. Before the 2005 amendment to the act, Section 11A(7) vested a patentee with the right to sue for infringement once the acceptance/grant of the patent was published. However, this provision was amended in 2005 to recognise the right of a patent applicant to take action against acts of infringement which were committed between the date of publication of the patent application and the date of grant of the patent.

If the intention of the legislature was to forbid enforcement of a so-called “recent patent”, then the act would not have been amended in such a way. The obvious conclusion is that if an act of infringement between the date of publication and the date of grant is actionable, then so too is an act of infringement after the date of grant, regardless of its temporal proximity to the date of grant.

It is ironic that even five years after the amendment of the act, the recent patent rule is applied to existing precedents without verifying their origins or their legitimacy under the existing law. It must also be understood that the spirit behind any rule of caution is to prevent the enforcement of patents which have not been used. Provided that the patented invention has been worked reasonably or steps have been taken to work the invention in India, an interim injunction should not be denied, subject to other requirements of the grant of an interim injunction being satisfied.

Further, technology continues to evolve due to an increasing emphasis on greater innovation and rapidly changing customer choices. Therefore, in the absence of the timely enforcement of patents citing extra statutory reasons, an exclusionary right such as a patent right is rendered toothless, and hence academic.