When can abandoned patent applications be used as prior art?

Abandoned patent applications can be used as prior art under specific circumstances:

• When they have been appropriately disclosed, such as being referenced in another patent’s disclosure, in a publication, or by voluntary disclosure.
• When they become publicly accessible.

As stated in the MPEP:

“An abandoned patent application may become evidence of prior art only when it has been appropriately disclosed, as, for example, when the abandoned patent [application] is reference[d] in the disclosure of another patent, in a publication, or by voluntary disclosure under [former Defensive Publication rule] 37 CFR 1.139 [Reserved].” Lee Pharmaceutical v. Kreps, 577 F.2d 610, 613, 198 USPQ 601, 605 (9th Cir. 1978).

It’s important to note that an abandoned application becomes available as prior art only from the date the public gains access to it, as per 37 CFR 1.14(a)(1)(ii) and (iv).

To learn more:

• abandoned applications
• prior art
• patent disclosure
• public access
• patent law