The main legal point established in the judgment is the requirement of deceptive similarity for trademark infringement and passing off, as well as the principles governing the grant or refusal of interlocutory injunctions.

JUDGMENT

Amit Mahajan, J. - The appellant, Sun Pharmaceutical Laboratories Ltd. (hereinafter referred to as 'SUN'), has filed the present appeal impugning an order dated 29.04.2022 (hereinafter referred to as the 'impugned order') passed by the learned Commercial Court.

2. The learned Commercial Court, by way of the impugned order, dismissed SUN's application under Order 39 Rules 1 & 2 of the of Civil Procedure, 1908 (hereinafter referred to as 'the CPC') in the suit bearing no. CS DJ (Comm.) No. 300/19.

3. SUN had filed the suit, inter alia, alleging infringement of its trademark 'LETROZ' and passing off and seeking a decree of permanent injunction restraining the respondent (defendant) from using the trademark 'LETERO', in respect of the pharmaceutical product in question.

4. Sun claims to be one of the largest generic medicine manufacturing pharmaceutical companies in the world. Amongst other pharmaceutical products, it also manufactures a generic drug for second line treatment of advanced breast cancer containing an active ingredient 'LETROZOLE' under the trademark 'LETROZ'. Sun claims that it is doing so since 01.09.2001.

5. SUN applied for registration of the trademark 'LETROZ' falling under Class 5 on 16.04.2001. The said application was objected/opposed by Novartis AG on the ground that 'LETROZ' is deceptively similar to the international non-proprietary name (INN) 'LETROZOLE'. SUN secured registration of the trademark 'LETROZ' on 14.10.2010 under Class 5.

6. SUN claims that sometime in the fourth week of November 2017, it came across a similar drug (with LETROZOLE as the active pharmaceutical ingredient) being manufactured by Hetero Healthcare Ltd. (hereinafter referred to as 'HETERO') under the mark 'LETERO'. FAO

7. It is not disputed by the parties that the drug being sold by SUN and HETERO is the same generic drug derived from the active ingredient 'LETROZOLE'.

8. SUN claims that due to the superior quality and high efficacy of the product, its sales increased to ?8.34 crores in the year 2016-17. It also claims that it had incurred huge expenses towards the publicity of its product 'LETROZ'. It acquired immense reputation and goodwill in the said trademark and the goods sold thereunder.

9. SUN further claims that on account of registration, it has a statutory right to exclusively use the registered trademark 'LETROZ'. And, it is entitled to an order restraining HETERO from using the trademark 'LETERO' as it is deceptively similar to its registered trademark 'LETROZ'.

10. It is alleged that HETERO has started using the impugned mark 'LETERO' in the year 2017 in order to pass off their goods as those of SUN and is trying to ride on the goodwill and reputation earned by SUN.

11. The injunction was, thus, sought alleging not only infringement of the trademark but also passing off the goods by HETERO as those of SUN.

12. HETERO contests the claims made by SUN. It contends that the word LETROZ is derived from the word 'LETROZOLE', which is an international non-proprietary name (INN) of a salt; therefore, SUN cannot claim monopoly in use of the said word. The word / mark LETROZ, is the first six letters of the said INN and its registration does not entitle SUN to claim exclusive rights in respect of the word LETROZOLE or any part thereof.

13. HETERO contends 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'.

14. It further claimed that HETERO has trademarks registered for various other products, where it has been using the mark by combining the last four letters of its name that is 'TERO' with other letters, making it a distinctive and coined mark.

15. HETERO further claims that even otherwise SUN, being aware of the use of the mark by HETERO since the ye