What happens if a preliminary amendment cancels all claims in a patent application?
If a preliminary amendment cancels all claims in a patent application without presenting new or substitute claims, it will not be entered by the USPTO. The MPEP states, A preliminary amendment filed in compliance with 37 CFR 1.121 will be entered unless it is disapproved by the Director. A preliminary amendment will be disapproved by the Director if the preliminary amendment cancels all the claims in the application without presenting any new or substitute claims.
This policy is based on the decision in Exxon Corp. v. Phillips Petroleum Co., 265 F.3d 1249, 60 USPQ2d 1369 (Fed. Cir. 2001). In such cases, the application will not be denied a filing date, but for fee calculation purposes, the Office will treat the application as containing only a single claim. The applicant will typically receive a notice of non-compliant amendment and be required to submit an amendment that complies with 37 CFR 1.121.
To learn more: