One possible reason is patentability-destroying prior art found in a
corresponding non-US application. Section 2001.06(a) of the Manual of
Patent Examining Procedure places a 'duty' on the applicant to notify the
US examiner of 'material prior art or other information cited or brought to
their attention in any related foreign application.' If the applicant does
not comply with this duty, they may receive a US patent, but they likely
will have great difficulty should they attempt to assert that US patent.
Consider the following possible sequence of events.
-US application is filed
-PCT application is filed with EPO as International Searching Authority
-US examiner allows application
-Applicant pays US Issue Fee
-EPO provides International Preliminary Examination Report with X
references missed by the US examiner
-Applicant files US continuation with amended claims
-Applicant files US Information Disclosure Statement with EPO's references
-Applicant withdraws original US application
-USPTO publishes bibliographic entry for the non-patent with note that 'all
references should be deleted'
-Database producers add the non-patent to their databases
There may be other reasons to withdraw an application, but I confess
familiarity with only this one.
Special note to Mr. Walter Bolger, EPO Examiner: Thank you for describing
the EPO's broad collection of databases and superior tools for using them
at the 1999 PIUG Meeting.
R.B. Luke
Intellectual Property Manager
ChemFirst Inc.
rluke@chemfirst.com