Delhi High Court rules on presumption of validity under Indian patent law

In a May 30 2014 decision in the case of 3M Innovative Properties Company v M/S Venus Safety & Health Pvt Ltd, the Delhi High Court reversed its previous order of December 18 2013, which had issued an ex parte interim injunction against Venus, restraining it from infringing 3M’s Indian patent.

A key aspect of this decision was the court’s ruling on the presumption of validity of a patent and the relative irrelevance of the six-year rule in Indian patent law.

Presumption of validity and six-year rule
The six-year rule of Indian patent law can be traced to the 1965 decision of the Madras High Court in Manicka Thevar v Star Ploughs, which borrowed the rule from English patent law.

According to this rule, a court will not grant an interim injunction in the case of recently granted patents – with 'recent' being less than six years. The rule presumes that patents older than six years are valid and therefore removes the need to examine the validity of the patent at the interim stage. Thus, the chances of an interim injunction being granted are substantially higher if a court does not investigate issues of patent validity.

Although the six-year rule was followed by the Indian courts as recently as 2007, subsequent decisions have ignored the rule. For example, in Roche v Cipla (148 (2008) DLT 598), the Delhi High Court expressed its bafflement at the rule and cautioned against a ritualistic application of it. Similarly, the Madras High Court declined to follow this rule in Mariappan v AR Safiullah (2008 (38) PTC 341 (Mad)).

Decision
In the case at hand, the six-year rule made a comeback. The order for an ex parte interim injunction issued on December 18 2013 cited the rule to conclude that the patent at issue was valid. However, the May 30 2014 ruling, which vacated the initial ex parte injunction, expressed the court's reservations about the rule.

The Delhi High Court cautioned that:

“[the] rule of presumption of validity after six years is not to be applied strictly in every case. It depends upon case to case basis and its merits, nature of defence raised and the evidence available on record which is produced by the defendant.”

However, the ruling made a concession to patentees when it stated that:

“it is correct that in case the patent in question has been tested in earlier cases and before the patent office in favour of the patentee, in those type of cases, the burden on the Defendant to demonstrate credibility would be of a higher degree.”

Thus, it appears that the court will be willing to presume a patent valid if it has survived previous litigation. This is an important concession because previous judgments – particularly that of the Supreme Court in Biswanath Prasad Radheyshyam v Hindustan Metal Industries ((1979) 2 SCC 571)) – have been clear in concluding that an Indian patent cannot be presumed valid. 

Returning to the present case, the court examined the validity of the patent at issue in light of the prior art produced by the defendant and concluded that the validity of the patent was in serious doubt. Therefore, the court concluded that the patentee had failed to establish a prima facie case.

The court also examined the other grounds for granting an interim injunction, such as the balance of convenience and irreparable injury, before deciding to vacate the ex parte interim injunction. The case is currently posted for trial.

Comment
Patentees who have successfully defended their patents in litigation should highlight such victories when they are trying to establish a strong prima facie case for the grant of an interim injunction. If the patent has not been tested in previous litigation, the court will likely conduct a mini-trial at the interim stage by examining the validity of the patent in light of prior art submitted by the patent owner.