Patent holders that introduce new claims when trying to correct a patent must ensure those claims meet the requirements in the original patent, a federal appeals court ruled.

The U.S. Court of Appeals for the Federal Circuit June 17 said Flow Valve LLC’s reissue patent claimed an invention that the original patent lacked. As a result, the reissue claims “don’t comply with original patent requirement of 35 U.S.C. § 251 as a matter of law,” the panel said, affirming a decision to invalidate the patent.

Forum US Inc., a Delaware company, argued in its summary judgment motion that Flow Valve’s...