The US Supreme Court has agreed to review the legality of so called pay for delay agreements where the owner of a branded drug pays another drug company not to bring a generic version of that drug to market for an agreed time period.

Such agreements are one tool used by patent holders to effectively extend the period of exclusivity of their drug on the market. They allow the patent holders to charge higher prices than if a generic equivalent were also available. Legal challenges to the practice have been going through the courts for a number of years, with varying outcomes.

Some generic drug manufacturers have challenged a patent, and often the company holding …