Delhi High Court Says Patent Amendments Permissible At Appellate Stage, Sets Aside Daikin Refusal

The Delhi High Court on 26 February reiterated that patent amendments are permissible even at the appellate stage, so long as they fall within the statutory framework of the Patents Act.

Justice Jyoti Singh partially allowed the appeal filed by Daikin Industries Ltd, setting aside the Patent Office order that had earlier denied the company a patent for its 'Shell-And-Plate Heat Exchanger.'

Observing that the specific modifications proposed by the company were permissible, as they neither broadened the invention's original scope nor deviated from the descriptions in the initial application, Justice Singh remarked:

“I am of the view that the amendment sought does not broaden the scope of unamended claim in any manner and its subject matter is disclosed in the specification.”

The case reached the High Court after the Assistant Controller of Patents and Designs rejected Daikin Industries Ltd's application in April 2024, on the ground that the invention lacked novelty based on a prior art document from 1972.

In its pleadings, Daikin contended that this old patent did not disclose the specific efficiency-enhancing features of its heat exchanger. The company further argued that the United States Patent and Trademark Office (USPTO) had already granted an identical patent after considering the same prior art.

To address the objections raised by the Indian regulator, Daikin submitted an auxiliary request to the Court, seeking to merge a dependent claim into its main claim. During the proceedings, the Patent Office conceded that, as a matter of law, claim amendments can be carried out even while an appeal is pending.

In support of this position, the Court referred to the precedent in Fresenius Medical Care Deutschland GmbH, which in turn relied on Nestle SA and Opentv Inc. These rulings established that the High Court, while hearing an appeal against a refusal, possesses “the same powers as given to a Controller... which includes the powers to require amendment.”

Justice Jyoti Singh observed that Daikin's request was valid under Section 59 of the Patents Act. The Court set aside the original refusal and remanded the matter to the Assistant Controller for a fresh decision based on the revised claims.

The Court directed Daikin to file its complete amended specifications before the Patent Office and mandated that the regulator conduct a new hearing.

While Justice Singh clarified that the Court had not expressed any opinion on the merits of the case, she ordered that the Patent Office endeavour to reach a final decision within two months of receiving the updated filings.