The preponderance of the evidence standard is the appropriate one for assessing invalidity during reexamination. Here, for example, the PTO found the claimed method at issue to be obvious and therefore unpatentable under a preponderance of the evidence standard even though the PTO had previously found allowed the patent to issue. “[O]nly after the patent issued [from the reexamination] would it be entitled to the presumption of validity under § 282.” This would be a good case to consult before asserting a weighing-of-the-evidence argument during reexamination.

Background / Facts: The patent on appeal here from rejection at the PTO during reexamination is directed to the making of contact-lens material. The PTO found that the claimed method at issue was obvious and therefore unpatentable under a preponderance of the evidence standard.

Issue(s): Whether the PTO in a reexamination proceeding must establish that the reexamined claims are not patentable by clear and convincing evidence rather than a preponderance of the evidence.

Holding(s): No. “The district court here was reviewing the Patent Office’s reexamination of claimed subject matter, and its final determination that the subject matter is not patentable, to ascertain whether [the patentee] was entitled to receive a patent. Only if the district court found in favor of [the patentee] would the Patent Office be authorized to issue a patent. See 35 U.S.C. § 145. And only after the patent issued would it be entitled to the presumption of validity under § 282 and, consequently, could not be held invalid absent clear and convincing evidence.”

Full Opinion