MPEP § 1875.02
The International Preliminary Examining Authority shall transmit to the applicant, preferably at the latest together with the international preliminary examination report, any decision which it has taken under Rule 68.3(c) on the protest of the applicant against payment of additional fees where the international application is considered to lack unity of invention. At the same time, it shall transmit to the International Bureau a copy of both the protest and the decision thereon, as well as any request by the applicant to forward the texts of both the protest and the decision thereon to the elected Offices.
Applicant may reply directly to the International Preliminary Examining Authority issuing the invitation by paying some or all additional fees or by restricting the claims to one invention. If applicant makes no reply within the set time limit, the international preliminary examination will proceed on the basis of the main invention only.
If applicant has paid an additional fee or fees, a protest to the holding of lack of unity of invention may be filed with the International Preliminary Examining Authority. The IPEA/US does not charge a protest fee under PCT Rule 68.3(e).
Form PCT/IPEA/420 is used by the Technology Center (TC) to inform the applicant of the decision regarding applicant’s protest on the payment of additional fees concerning unity of invention.
The TC checks the appropriate box, i.e., 1 or 2. If box 2 is checked, a clear and concise explanation as to why the protest concerning the unity of invention was found to be unjustified must be given.
Since the space is limited, supplemental attachment sheet(s) should be incorporated whenever necessary.
Form PCT/IPEA/420 must be signed by a TC Director. See MPEP § 1002.02(c), item (2).