Patent challenges just got harder for companies that want to invalidate a rival's patent

The US Patent and Trademark Office is changing the rules for challenging patents. It will now be harder to invalidate a patent once it has been granted.

For years, companies could challenge a rival's patent through a process called inter partes review, which was often faster and cheaper than going to court. This process allowed competitors to clear out patents they believed were weak or invalid. These new rules make it more difficult to use that process, which means patents will be harder to overturn.