No Exclusivity over INNs – Delhi High Court Denies Injunctive Relief to Sun Pharma

LexOrbis India

International Non-proprietary Names (INNs) are considered as generic names for pharmaceutical substances. According to the definition published by WHO, an INN “identifies a pharmaceutical substance or active pharmaceutical ingredient by a unique name that is globally recognized and is public property”. As the name implies, these names are "non-proprietary" and cannot be used to designate or identify pharmaceutical compounds by any person or organisation exclusively. With the goal to provide easily recognisable and globally uniform names to pharmaceutical substances, the World Health Assembly introduced International Non-Proprietary Names way back in 1950 and has been updating the list ever since. In India too, the trademark registration of an INN or a deceptively similar name thereto is prohibited under Section 13 of the Trademarks Act (“Act”). The provision clearly states that any word which has been declared by the World Health Organisation as an INN (and notified by the Registrar of Trademarks to be so) or a name deceptively similar thereto is not registrable as a trademark. Furthermore, Section 13 provides that any such registration will be deemed to be an entry made in the Register without sufficient cause or an entry wrongly remaining on the Register. Indian Trademark Registry notifies the list of INNs on its website which can be accessed here -  

Despite the express bar on the registration of INNs and names similar thereto; quite a few marks get erroneously registered, and attempts are often made to gain exclusivity over them. Indian courts have and continue to encounter issues related to enforcement of such trademarks which are hit by this prohibition. The position taken by courts in various cases has broadly remained the same all along, the crux whereof is that INNs and the names similar thereto cannot be monopolized. In the recent case of Sun Pharmaceutical Laboratories Ltd. v. Hetero Healthcare Ltd. and Anr. FAO (COMM) 96/2022, the Delhi High Court added another leaf to the jurisprudence on the issue of INNs as trademarks. The court dismissed the appeal filed by Sun Pharmaceutical Laboratories Ltd. ("Sun Pharma") against the Commercial Court’s order refusing to grant an injunction in its favour in a suit for infringement and passing off against the respondent Hetero Healthcare Ltd. (“Hetero”). As far as the factual matrix goes, the issue arose between Sun Pharma and Hetero, which were using the marks LETROZ and LETERO respectively for a drug, the active ingredient for which is Letrozole.

Before the Commercial Court, Sun Pharma contended that it was one of the largest generic medicine manufacturing pharmaceutical companies in the world and that it had been manufacturing a generic drug for second line treatment of advanced breast cancer containing the active ingredient Letrozole under the trademark LETROZ, registered in Class 5 since 01.09.2001. In 2017, it discovered that the mark LETERO was being used by the Respondent Hetero. Sun Pharma relied on its registration to claim that it had the statutory right to exclusively use its trademark LETROZ and that it was entitled to an order restraining Hetero from using the trademark LETERO, because it was deceptively similar to its registered trademark LETROZ.


Hetero, in its defence, argued that its mark LETROZ was derived from the word Letrozole, which is an international non-proprietary name (INN) of a salt; therefore, Sun Pharma was not entitled to claim monopoly over the said word. Hetero further contended that it is common practice in the pharmaceutical industry to use trademarks derived from the active pharmaceutical ingredient (API). It further argued that the mark LETERO is a registered trademark of Hetero and is coined by combining the first two letters of the salt LETROZOLE with the last four letters of Hetero, that is ‘TERO’. It also alleged acquiescence on Sun Pharma’s part saying they had been aware of Hetero’s use of the mark LETERO since 2007.

After going through these contentions, the Commercial Court held that there was no deceptive similarity between the competing marks which could confuse a doctor or a chemist and that it was beyond understanding as to how the plaintiff could stop the defendant from using first two alphabets when they themselves were using all the 6 alphabets LETEROZ of the generic name i.e LETROZOLE. Therefore, the application for injunction filed by Sun Pharma was dismissed. Sun Pharma filed an appeal against the decision.

Delhi High Court laid heavy reliance on the case Schering Corporation & Ors. v. Alkem Laboratories Ltd. 2009 SCC OnLine Del 3886, wherein the Coordinate Bench held that the appellant’s marks TEMODAL and TEMODAR were not deceptively similar to the respondent’s marks TEMOKEM and TEMOGET as the word “TEM/TEMO” was publici juris; and also generic for and descriptive of the chemical component Temozolomide because of which the appellant could not claim an exclusive right to the use thereof. Relying on this judgment, the court held as follows:

 “In our opinion, the judgment and the ratio laid down in Schering Corporation & Ors. v. Alkem Laboratories Ltd. (supra), squarelyapplies to the facts of the present case. The appellant, in the present case, cannot be allowed to monopolize the INN ‘LETROZOLE’. The mark, ‘LETROZ’, is not similar to the trademark ‘LETERO’ merely because both the parties have adopted the initial letters (SUN adopted the first six and HETERO adopted the first three) of the INN ‘LETROZOLE’. It is apparent that both SUN and HETERO are using their marks, which are derived from the INN ‘LETROZOLE’, which is descriptive of the active ingredient of the drug, that is, ‘LETROZOLE’.

In the present case, there is also a marked difference in the price of both the products being sold by SUN and HETERO. SUN is selling its product at ₹187.80/- and HETERO is selling it for ₹60/-. 37. The learned Commercial Court found that the trademarks in question were not similar. We concur with the prima facie view of the learned Commercial Court.”

The court also referred to the case of Panacea Biotec Ltd. v. Recon Ltd 1996 SCC OnLine Del 508 wherein the plaintiff was using the trademark NIMULID and it filed a suit seeking injunction against the defendant from using the mark REMULIDE in relation to the same medicine with the API being NIMESULIDE. In this case, the court held that when the name of a drug is derived or coined from the name of the principal ingredient being used in the manufacturing of that drug, no distinctiveness or exclusiveness can be claimed by the manufacturer in that name.

The court found that the above cases are applicable to this case and the mark LETROZ is nothing but a short name of the active ingredient Letrozole. In light of this, the Court held that the Appellant could not be allowed to monopolize the INN Letrozole. One of the points that the Court emphasized on was that, for the treatment of an ailment as serious as breast cancer, it was difficult to accept that a medical practitioner prescribing the drugs for its treatment, would be confused because the initial three letters of the marks which are derived from the INN, are same.


The decision of the court is in line with the globally accepted principles around INNs. Registration and enforcement of such marks which are derived from INNs and are deceptively similar thereto would create confusion in drug nomenclature and would indeed amount to allowing monopoly over generic names for drugs which should ideally be available for use by all. Since the clear identification basis INNs helps in ensuring safe prescription and dispensing of medicines to patients, the said purpose will be negated if the marks starkly similar to INNs proceed to registration and are granted monopoly over. Indian Trade Marks Registry must assess all pharmaceuticals related trademarks in light of the published list of INNs. All marks which are hit by the prohibition embodied under Section 13 of the Trade Marks Act, must not be granted registration. Once the registration is granted, the parties try to enforce such registration by asserting exclusivity over them owing to which cases involving the INNs are tabled before courts. Careful assessment of marks by Trade Marks Registry at the time of examination of trademarks applied for registration can save courts’ time and nip any efforts of monopolizing INNs in the bud.


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