Delhi High Court Upholds Helsinn's Anti-Nausea Drug Patent, Dismisses Zydus Challenge
Key Insights
The Delhi High Court (search) rejected Zydus Healthcare's challenge to Helsinn Healthcare's patent for nausea (search) and vomiting (search) medication, ruling that no procedural violations occurred during the patent grant process.
Justice Tejas Karia clarified that pre-grant opposition proceedings and patent examination are distinct processes, with opponents having no right to additional hearings during the examination stage.
The court dismissed the petition on territorial jurisdiction grounds, stating that challenges to Patent Office (search) orders must be filed in the High Court where the relevant Patent Office is located.
The Delhi High Court (search) has dismissed a patent challenge by Indian pharmaceutical company Zydus Healthcare Ltd against Swiss drugmaker Helsinn Healthcare SA's anti-nausea medication (search) patent, upholding the Patent Office (search)'s decision to grant the intellectual property rights.
In a judgment dated December 24, 2025, Justice Tejas Karia ruled that the Patent Office (search) committed no jurisdictional error and did not violate principles of natural justice while granting the patent. The court clarified that proceedings relating to patent application examination and pre-grant opposition are distinct and independent processes under the Patents Act.
Patent Details and Opposition Timeline
The patent in question relates to an invention titled "Compositions and Methods for Treating Centrally Mediated Nausea (search) and Vomiting (search)." Helsinn Healthcare filed its patent application in April 2012 with 51 claims.
During prosecution, Helsinn sought voluntary amendments, stating that these were necessary to more clearly define the invention. A First Examination Report was later issued by the Patent Office (search), following which further amendments were made.
Zydus filed a pre-grant opposition, alleging that the amendments impermissibly expanded the scope of the claims and that mandatory requirements under the Patents Act and Rules were not complied with. A hearing on the opposition was held in May 2022, after which the Patent Office (search) reserved its order.
After reserving its decision on the opposition, the Patent Office (search) issued a separate hearing notice to Helsinn during the examination stage. Additional amendments followed. In March 2023, the Patent Office rejected Zydus' pre-grant opposition and granted the patent to Helsinn.
Court's Legal Analysis
Zydus approached the Delhi High Court (search), arguing that it ought to have been given another opportunity for a hearing and that denial of such a hearing violated principles of natural justice. Senior Advocate Dayan Krishnan, representing Zydus Healthcare, contended that the Patent Office (search) should have granted the company an additional hearing after further amendments were made to the patent claims during the examination stage.
Rejecting this contention, the court noted that the grounds raised by Zydus had already been considered during the pre-grant opposition hearing. The subsequent examination proceedings, it said, were independent of that process.
"The right of hearing of the opponent under Rule 55 of the Rules is confined to a consideration of issues raised in the Pre-Grant Opposition. The two processes are separate from each other as the examination process demands a focused evaluation of the application while the opposition process is to address the concerns of external stakeholders," the Court said.
Jurisdictional and Procedural Rulings
On the issue of claim amendments, the Court held that there is no legal requirement to pass a separate order on voluntary amendments made before the issuance of the First Examination Report.
The court also declined to entertain the petition on territorial jurisdiction. It held that in writ petitions challenging Patent Office (search) orders, jurisdiction lies with the High Court within whose territorial limits the concerned Patent Office is situated. Since the patent was granted by the Mumbai Patent Office (search), the Delhi High Court (search) lacked jurisdiction.
Senior Advocate Amit Sibal, representing Helsinn Healthcare, defended the grant of the patent, submitting that the statutory framework clearly differentiates between examination and opposition proceedings and that Zydus had no vested right to be heard beyond the pre-grant opposition stage.
"A pre-grant opposition and examination are two separate and independent proceedings," Justice Karia noted, agreeing with Helsinn's position that opponents have no right to participate in or seek a hearing during the examination of the patent application.
Finding no procedural illegality or breach of natural justice, the court dismissed Zydus Healthcare's petition and upheld the patent granted to Helsinn Healthcare.