Fletcher YoderThe Court has a duty to wholly review the prosecution process including prosection laches (e.g., unreasonable delays and prejudice attributable to delays) in determining whether patents are enforceable.
The PTO may assert a prosecution laches defense in an action under 35 U.S.C. § 145 when a patent applicant inexplicably and unreasonably delays prosecution of their patent application.
Declaratory defendant’s asserted patent claims are unenforceable under doctrine of prosecution laches, since defendant, through sequential filing of applications, delayed from 18 to 39 years in filing and prosecuting claims, and since such delay was unreasonable and unjustified.