Alkem Laboratories v. Numen Pharma (2026): ALCIPRO and ACIPROX are confusingly alike, and a 'bare possibility' of confusion suffices for medicines

When two drug names sound alike, the law worries less about the discerning shopper and more about the harried pharmacist deciphering a doctor's handwriting. That instinct — that medicines demand a sterner standard than ordinary consumer goods — has animated Indian trade-mark law since Cadila Health Care Ltd. v. Cadila Pharmaceuticals Ltd. On 8 June 2026, in a passing-off and infringement action between two pharmaceutical companies, Justice Sharmila U. Deshmukh of the Bombay High Court applied that standard once more, granting an interim injunction in Alkem Laboratories Ltd. v. Numen Pharma Private Limited.

The facts in brief

Alkem Laboratories adopted the trade mark "ALCIPRO" in 1990 and secured its registration in Class 5 on 4 April 1990, later extending the family to variants such as "ALCIPRO-TN" and various strengths and formulations. The ALCIPRO range is used to treat bacterial and urinary-tract infections and contains the active pharmaceutical ingredient ciprofloxacin.

Around December 2023 Alkem learnt that Numen Pharma had advertised an application to register the mark "ACIPROX", filed on a proposed-to-be-used basis, with the defendant later claiming use from 2023. Numen's product, by contrast, contained aceclofenac and was used for short-term relief of pain and inflammation. Alkem opposed the registration and sued; on 8 October 2025 the Court had already granted ad-interim relief against infringement of the registered mark. The order of 8 June 2026 disposed of the interim application after the matter was reserved on 24 April 2026.

The question

The contest, as the Court framed it, was simply "ALCIPRO" versus "ACIPROX". Numen had deleted the letter "L" and added a terminal "X". It argued that "CIPRO" was descriptive of ciprofloxacin and could not be monopolised; that the marks, compared as wholes, were neither identical nor deceptively similar; that it always used "ACIPROX" with distinguishing suffixes denoting strengths and formulations; and that, because the two products treated entirely different conditions and were prescription drugs, no real confusion could arise. Crucially, Numen also urged the Court to compare the marks syllable by syllable — ACIPROX as "A-SI-PROX" against ALCIPRO as "AL-SI-PROX" — to show they were phonetically distinct.

What the Court held

The Court rejected the syllable-by-syllable approach as impermissible, invoking the anti-dissection rule applied by the Division Bench in Sun Pharmaceutical Industries Ltd. v. Meghmani Lifesciences Ltd. (which had compared "RACIRAFT" against "ESIRAFT" as wholes). Compared in their entirety, the Court found, ACIPROX and ALCIPRO were phonetically similar; mispronounced or hurriedly uttered, they would sound alike, and the trailing "X" was liable to be slurred over and insufficient to distinguish the marks. Greater care was warranted, the Court added, precisely because the two compositions differed.

The Court drew directly on the Supreme Court's reasoning in Cadila and Milmet Oftho Industries v. Allergan Inc.: that exacting scrutiny is required where confusion over medicinal marks could cause harm far graver than confusion over ordinary goods, and that even physicians and pharmacists are not immune from error — many prescriptions are telephoned in or handwritten, often illegibly. The fact that both were prescription drugs therefore did not foreclose confusion. On Numen's descriptiveness defence, the Court held that the prohibition in Section 13 of the Trade Marks Act 1999 (against registering an international non-proprietary name) post-dated Alkem's 1990 registration, that ALCIPRO was not in any event deceptively similar to the INN, and that under Section 31 the registration was prima facie evidence of validity. The "common to the trade" defence failed for want of evidence of extensive third-party use.

Analysis

The decision is a faithful application of the Cadila line rather than a doctrinal departure, but it is instructive in how it disposes of the most common defensive moves in pharmaceutical mark disputes. First, dissection: a defendant who pronounces the rival marks slowly and segments them into syllables will not be heard, because the anti-dissection rule requires the marks to be weighed as wholes and against the realities of a multilingual, partly illiterate consuming public. Second, the difference-in-composition argument cuts the wrong way — where the active ingredients differ, the consequences of a mix-up are graver, so the case for restraint is stronger, not weaker. Third, the prescription-only character of both drugs is no shield, given the well-documented fragility of the prescription-to-dispensing chain.

The treatment of the descriptiveness and INN defences is also worth noting. Numen's contention that "CIPRO" merely denoted ciprofloxacin ran into both the chronology of Section 13 (the relevant INN notification came in 2012, long after the 1990 registration) and the prima-facie-validity presumption in Section 31. A registrant with a long-standing mark thus enters such a contest with a structural advantage that a generic-derivation argument, unsupported by evidence of widespread trade use, will rarely overcome at the interim stage.

Why it matters

For pharmaceutical companies, the ruling reaffirms that brand selection clearance must assume the bare possibility standard, not the ordinary "likelihood of confusion" calibration used for fast-moving consumer goods. A single shared, pronounceable stem and a near-identical overall sound can sink a new mark even where the molecules, indications, and packaging diverge. For litigators, the order is a clean template: lead with the registered mark's seniority and Section 31 validity, anchor the phonetic comparison in the anti-dissection rule, and meet the descriptiveness defence with both chronology and an evidentiary demand for extensive third-party usage. For the broader doctrine, it is one more reminder that in medicinal marks the public-health rationale tilts the balance of convenience firmly toward restraint.

Related on Valkya

• Emami v. Dabur (Cool King): trade-dress passing-off and the composite-imitation test
• Flipkart v. Marc Enterprises: MARQ, MARC and the contours of phonetic similarity in passing-off
• Delhi HC on Google Ads keyword bidding as trade-mark infringement (Hindware)

Sources

• Bombay High Court order in Alkem Laboratories Ltd. v. Numen Pharma Pvt. Ltd. (IA No. 1606 of 2026 in Comm. IP Suit No. 679 of 2025), 8 June 2026 (PDF)
• LiveLaw: "'Bare Possibility Of Confusion' Enough In Pharma Marks: Bombay High Court Restrains Use Of 'ACIPROX'"