Can a patent application under a Secrecy Order be issued or involved in an interference?

No, patent applications under Secrecy Orders are not issued and cannot be involved in interferences or derivation proceedings. The MPEP states: Secrecy Order cases are examined for patentability as in other cases, but will not be passed to issue; nor will an interference or derivation be instituted where one or more of the conflicting cases is classified or under Secrecy Order. This is further supported by 37 CFR 5.3 and MPEP § 2306.

For more information on patent issuance, visit: patent issuance.