Continuation-in-part application (CIP)

• Filed during the lifetime of the earlier application. A later-filed application must be copending with the prior application, meaning it is filed before the prior application is patented, abandoned, or its proceedings terminated³.
• Repeats the earlier disclosure and adds to it. It repeats some substantial portion or all of the prior-filed application and adds matter not disclosed in it².
• Filed under 37 CFR 1.53(b). A CIP may only be filed under 37 CFR 1.53(b), and cannot be filed as a continued prosecution application under 37 CFR 1.53(d)².
• Claims the benefit. It must claim the benefit of the prior-filed application under 35 U.S.C. 120, 121, 365(c) or 386(c)², and the reference must state that the later application is a continuation-in-part⁴.
• Common inventor. Under 35 U.S.C. 120 the later application must name an inventor or joint inventor named in the earlier application¹. A CIP with a sole inventor may derive from an earlier application with joint inventors, and the reverse, subject to the conditions of 35 U.S.C. 120 and 37 CFR 1.78².
• No acquiescence. Filing a CIP does not by itself create a presumption that the applicant acquiesces in rejections outstanding in the earlier application².
• Extra duty of disclosure. In a continuation-in-part the duty of disclosure includes information material to patentability that became available between the filing date of the prior application and the filing date of the continuation-in-part (37 CFR 1.56(e))⁷.

The question is answered claim by claim. The MPEP states that only the claims of the CIP that are disclosed in the manner provided by 35 U.S.C. 112(a) in the prior-filed application are entitled to the benefit of the prior-filed application's filing date³.

• If CIP claims that are entitled only to the CIP filing date read on published, publicly used or sold, or patented subject matter, a rejection under 35 U.S.C. 102 would be proper³.
• Where a parent is found fatally defective because its disclosure is insufficient to support allowable claims, a later-filed CIP that supplies the deficiency is not entitled to the benefit of the parent's filing date³.
• If there is a chain of copending applications, each application must disclose the claimed invention of the later-filed application in the manner provided by 35 U.S.C. 112(a) for the later application to get the earliest filing date³.
• Patent term is a separate question. Where an application contains a specific reference to an earlier application under section 120, the term ends 20 years from the filing date of the earliest such application⁵.

1. File while the parent is pendingThe CIP must be filed before the patenting or abandonment of, or termination of proceedings on, the earlier application or an application similarly entitled to its date (35 U.S.C. 120)¹. If the parent issues as a patent, filing on the issue date or before is sufficient³.
2. Refer to the parent and name the relationshipA nonprovisional application must refer to each prior-filed application in an application data sheet, and the reference must identify whether the later application is a continuation, divisional or continuation-in-part⁴.
3. Meet the deadlineFor an application filed under 35 U.S.C. 111(a), the reference is due within the later of four months from the actual filing date or sixteen months from the filing date of the prior-filed application⁴. Failure to submit it in time is considered a waiver of the benefit, unless a petition for an unintentionally delayed claim is granted⁴. The reference must be submitted with any fee due under 37 CFR 1.17(w)⁴, which applies when the CIP is filed more than six years after the earliest filing date for which benefit is claimed⁸.

One difference matters in practice. The Federal Circuit has concluded that the protection of the third sentence of 35 U.S.C. 121 does not extend to continuation-in-part applications, and is limited to divisional applications (Pfizer v. Teva, as quoted in the MPEP)². That sentence bars using a patent issued on the restricted parent as a reference against a divisional application, or against the original application, if the divisional application is filed before the issuance of the patent on the other application (35 U.S.C. 121)⁹. A CIP should not be designated as a divisional². For the provisional route, see provisional patent application: an application claiming the benefit of a provisional is not a continuation-in-part of it².

The Federal Circuit decided which filing date certain claims of a CIP could receive. The record below says nothing about either party beyond what the opinion states⁶.

The patent in suit issued from an application filed on March 24, 1987 as a continuation-in-part of an application filed on June 1, 1984. The court held that claims 1 and 9, which were generic as to cup shape, were not entitled to the parent's filing date because the parent specification disclosed only conical cups, and that they were invalid as anticipated by intervening prior art. It recorded that claims 2 and 10 were conceded to be supported by the parent6.