India, June 5 -- Apple faced a major legal blow after a federal appeals panel denied its emergency request to pause a court order that curbs its ability to collect fees on in-app purchases processed outside its App Store ecosystem.

The ruling, issued late Thursday by the Ninth Circuit Court of Appeals, allows significant changes to Apple's payment policies to remain in effect changes that could cost the company billions in annual revenue.

The dispute stems from a broader antitrust case brought nearly five years ago by Epic Games, which accused Apple of operating the App Store as a monopolistic platform. Central to the case were Apple's 15% to 30% commissions on digital purchases within iPhone apps, enforced through a strict ban on alterna...