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Delhi High Court Cancels DAPLOGIN Trademark Registration Over Deceptive Similarity With DAPLO

  • Writer: Kaustav Chowdhury
    Kaustav Chowdhury
  • 3 days ago
  • 4 min read

The Delhi High Court, in an order reported on August 20, 2026, has cancelled the trademark registration of DAPLOGIN, held by Razenta Pharma, on a petition filed by Dr. Reddy's Laboratories Limited. The court found that DAPLOGIN is deceptively similar to Dr. Reddy's prior registered trademark DAPLO, both of which are used for dapagliflozin based pharmaceutical formulations prescribed for the management of Type 2 diabetes. The ruling underscores the heightened standard of scrutiny that Indian courts apply when assessing trademark similarity in the pharmaceutical sector, where brand confusion can carry direct consequences for patient health and safety.


Background: The Marks and the Products


Dr. Reddy's Laboratories, one of India's largest pharmaceutical companies, markets its dapagliflozin formulation under the brand name DAPLO. Dapagliflozin is a sodium glucose co transporter 2 (SGLT2) inhibitor widely prescribed for the management of Type 2 diabetes mellitus and, in some cases, heart failure and chronic kidney disease. The drug works by preventing the reabsorption of glucose in the kidneys, causing excess glucose to be excreted through urine, and is among the most commercially significant molecules in India's diabetes care segment.


Razenta Pharma obtained registration for the trademark DAPLOGIN for a product in the same therapeutic category. Dr. Reddy's challenged this registration, arguing that DAPLOGIN is phonetically, visually and structurally similar to its prior mark DAPLO, and that the coexistence of both marks in the same therapeutic segment creates a real risk of confusion among patients, pharmacists and prescribing physicians. The challenge was brought under the rectification and cancellation provisions of the Trade Marks Act, 1999.


The Court's Analysis of Deceptive Similarity


The Delhi High Court applied the well established test for deceptive similarity under Section 2(1)(h) of the Trade Marks Act, 1999, which defines a mark as deceptively similar to another mark if it so nearly resembles that other mark as to be likely to deceive or cause confusion. The court examined the two marks on three parameters: visual similarity, phonetic similarity, and structural similarity.


On visual and structural similarity, the court noted that DAPLOGIN contains the entirety of DAPLO as its prefix, with the addition of the suffix GIN. The court observed that consumers, particularly patients who may not be familiar with the full spelling of their medication, are likely to focus on the first syllable or the dominant portion of the mark, which in this case is DAPLO. The addition of a common pharmaceutical suffix does not create sufficient distinction to avoid confusion.


On phonetic similarity, the court found that when spoken aloud, DAPLO and DAPLOGIN share the same initial sound and cadence, with the additional syllable in DAPLOGIN being insufficiently distinctive to prevent a pharmacist or patient from confusing one for the other. The court noted that in a busy pharmacy or clinical setting, where prescriptions are often communicated verbally, the risk of confusion is particularly acute.


Heightened Scrutiny for Pharmaceutical Trademarks


The court reaffirmed the principle, developed through a substantial body of Indian case law, that pharmaceutical trademarks attract a stricter standard of assessment than marks used for ordinary consumer goods. The rationale is straightforward: if a patient or pharmacist confuses one drug for another, the consequences can include wrong dosages, adverse drug interactions, and potentially serious health outcomes. This is especially relevant in the diabetes treatment space, where drugs with different active ingredients, dosage requirements and contraindications may carry similar sounding brand names.


Indian courts have consistently held that the test for deceptive similarity must be applied from the perspective of a person of average intelligence and imperfect recollection, and that in the pharmaceutical context, this standard must account for patients who may be elderly, have limited literacy, or rely on verbal instructions from their doctors. The court held that applying this standard, DAPLOGIN is likely to cause confusion with DAPLO and ordered the cancellation of the DAPLOGIN registration.


Implications for the Pharmaceutical Industry


The ruling reinforces the position that established pharmaceutical companies can successfully challenge later registrations of marks that incorporate their existing brand as a prefix or dominant element. For smaller manufacturers and generic drugmakers, the judgment serves as a warning that adopting a brand name that closely resembles an established mark in the same therapeutic category carries significant legal risk, even if additional suffixes or prefixes are added to create superficial differentiation. The decision also signals to the Trade Marks Registry that greater diligence is required at the examination stage to identify and refuse applications for marks that are deceptively similar to existing registrations in the pharmaceutical class.


For the broader pharmaceutical industry, the judgment adds to the growing body of case law establishing that courts will prioritise patient safety over commercial convenience when adjudicating drug name disputes. Companies planning to launch new formulations should invest in comprehensive trademark clearance searches and consider the phonetic, visual and structural dimensions of similarity before committing to a brand name.


Key Takeaways


  • The Delhi High Court has cancelled the DAPLOGIN trademark registration held by Razenta Pharma, finding it deceptively similar to Dr. Reddy's prior mark DAPLO.

  • Both marks cover dapagliflozin based diabetes medications, making the risk of patient and pharmacist confusion a central concern.

  • Adding a common pharmaceutical suffix to an existing registered mark does not create sufficient distinction to avoid a finding of deceptive similarity.

  • Indian courts apply a heightened standard of scrutiny to pharmaceutical trademark disputes due to the potential health consequences of drug name confusion.

  • The test for deceptive similarity is applied from the perspective of a consumer of average intelligence and imperfect recollection, with additional sensitivity in the pharmaceutical context.

  • Pharmaceutical companies should conduct thorough trademark clearance searches before adopting brand names for new formulations.


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