Patents and prosecution

WASHINGTON — A federal court in Washington, applying precedent from the Federal Circuit, ruled that the doctrine of prosecution laches may be invoked as an affirmative defense by those who seek a finding that a patent is unenforceable. When the Patent and Trademark Office can show a patentee’s delay in prosecution is unreasonable and that such delay prejudiced an accused infringer, the defense may render the patent in question unenforceable.