In March 2026, Taiwan’s Supreme Court rendered a pivotal judgment, vacating the second-instance decision of the Intellectual Property and Commercial Court ("IPCC") that had previously ruled in favor of the biosimilar company, Celltrion Healthcare Taiwan (“Celltrion”).[1] Centering on a dispute between the Swiss pharmaceutical giant F. Hoffmann-La Roche AG ("Roche") and Celltrion, the Taiwan subsidiary of the Korean Celltrion, this case addresses whether a biosimilar manufacturer has the requisite "legal interest" to seek a declaratory judgment of non-infringement, before it has officially added back a patented indication on its generic version of regulatory approval. The Supreme Court’s decision underlies a clear boundary governing legal interests in declaratory lawsuits regarding pharmaceutical patent disputes in Taiwan.

  The dispute stems from Taiwan Invention Patent No. I380826, titled "Method for treating joint injury," owned by Roche. The patent claims a combination therapy of rituximab and methotrexate to treat patients suffering from rheumatoid arthritis ("RA"). Celltrion developed a biosimilar product named "Truxima" and received a regulatory approval from the Taiwan Food and Drug Administration ("TFDA") in March 2019. Originally, Truxima's approved labeling included RA as an indication. However, after receiving a warning letter from Roche alleging infringement of the ‘826 patent, Celltrion voluntarily deleted the RA indication from its approval. Subsequently, learning that the European counterpart patent had been revoked, Celltrion informed Roche in March 2020 of its “intention to re-add the RA indication” to Truxima's label. Roche replied with a warning letter demanding that Celltrion be not infringe. Seeking to clear out the commercial uncertainty, Celltrion filed a lawsuit requesting a judgment for declaring the absence of Roche’s entitlement based on the '826 patent for injunctions and damages award.

  The first-instance and appellate IPCC courts both sided with Celltrion. On the merits, the IPCC determined that while the patent was novel, the combination of several prior art references rendered the asserted claim 1 obvious and thus invalid. Because the grounds for revoking the ‘826 patent stand, the IPCC ruled that Celltrion faced no risk of patent infringement and possessed a valid legal interest to declaration of non-infringement. Roche appealed to the Supreme Court, arguing that Celltrion was seeking a declaration over a future legal relationship rather than a present one, which fails to constitute a cognizable legal interest.

  The Supreme Court turned its focus entirely to the procedural admissibility regarding the definition of legal interest for declaration protection. A declaratory action is only permissible if the plaintiff possesses an immediate legal interest to eliminate an existing uncertainty over a present relationship at law.[2] The Supreme Court stressed that unlike actions demanding future performance,[3] which are statutorily permitted under strict requirements, no such statutory exceptions are offered to declare future legal relationships. In view of the limited judicial resources, allowing parties to litigate hypothetical or future disputes over unestablished facts would impose an undue burden on courts and litigants alike.

  In the present case, the Supreme Court noted that any modification to add an indication to an existing regulatory approval requires formal review and approval by the TFDA before the drug can be lawfully marketed or labeled with that indication. Since Celltrion had previously deleted the RA indication, it could not lawfully distribute Truxima for RA before TFDA’s reissuance of the approval. Manifestly, the IPCC failed to first determine the status and progress of the approval’s reissuance. If the regulatory approval had not yet been reissued, Celltrion's request was merely seeking to confirm a future, contingent legal relationship rather than an ongoing and active dispute, which would not present a valid legal interest.

  Consequently, the Supreme Court vacated the lower court's judgment and remanded the case to the IPCC for further factual review.

  The Supreme Court's judgement carries distinct strategic implications for both brand-name and generic drug companies. Brand-name companies are advised to carefully audit the generic competitor's regulatory status and find loopholes to defend prematurity of a declaration challenge. On the opposite, generic and biosimilar manufacturers must recognize that taking a non-infringement declaratory action requires precise regulatory timing. Simply receiving a warning letter from a patentee is not a guarantee to establish a legal interest if the label based on which an action was filed is not yet finalized. They must ensure that their TFDA application is approved and thereby demonstrating an imminent present risk to their commercial status that justifiably supports a judicial resolution.

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