Double patenting seeks to prevent an unjustified extension of time beyond the term of a patent. Therefore, if an applicant files patent application 1 on date A and files a similar patent application 2 on date B, the second invention may be considered a double patent, and the right to exclude others of the patented technology should not be extending based on the later patent filing. Double patenting includes two main prongs: 1) a common owner, 2) the same claimed subject matter. For a further explanation of double patenting, look at MPEP section 804.

If the patent applications have at least one common inventor or are commonly assigned, then it is likely that the first prong is met. The second prong deals with the claimed subject matter, not the subject matter of the invention as a whole. This is because the doctrine of double patenting deals with avoiding unjustly extending patent rights at the expense of the public having access to the patent technology.

There are two types of double patenting, the first is termed “statutory double patenting.” Two separate patents cannot claim the exact same subject matter, so amendments to the claims are required under statutory double patenting because the subject matter is exactly the same. The second type of double patenting is called “obvious double patenting” or “non-statutory double patenting.” In this type of rejection, the examiner feels that the claims are so similar that they would are obvious.

To overcome a statutory double patenting rejection, the examiner is essentially saying the claims as written are exactly the same; therefore it is required to amend the claims. Sample language of how to overcome the a statutory doubly patenting rejection is as follows: “On page X of the office action dated January 1, 2013, the Examiner rejections claims 1-3 as being statutory double patenting. To expedite prosecution and without conceding to the examiner’s positions, Applicant has amended independent claims 1 to recite “x,y,z” or “new element 1.” Therefore, claims 1 recite different subject matter than what is recited in patent application 123, and amended claim 1 includes novel patentable subject matter. In view of the above, withdrawal of this rejection is respectfully requested. Additionally, when dealing with statutory double patenting rejections, the examiner missed an element of the claim that is novel. In these circumstances, pointing out to the examiner that the claims include elements not reviewed by the examiner will typically suffice to overcome the rejection.

To overcome a non-statutory double patenting rejection, Applicants are given a couple of more options including 1) holding the rejection in abeyance, 2) filing a terminal disclaimer, 3) amending the claims.

  1. When an Applicant holds a non-statutory double patenting in abeyance, essentially the Applicant is telling the examiner that prosecution is open on the applicant and there is a strong chance that the claims will be amended in the future, so there is no need to discuss this matter now. Thus, the rejection will be held in “abeyance” to be dealt with at a later time, if necessary. If a double patenting rejection is held in abeyance, it is important to address this before the application is granted. If not the granted patent may be held invalid if litigated. The second way to overcome a double patenting rejection is to file a terminal disclaimer.
  2. A terminal disclaimer essentially states that the later patent application will expire at the same time as the earlier patent and that the later patent application will only be enforceable if they are commonly owned. Terminal disclaimers are easy to use when 1) you know your company will hold an interest in the patent or will be sold together, it doesn’t need to be a 100% interest just some interest and the patent application is a continuation.  If the patent application is a continuation, then they will expire at the same time, so nothing is lost from a timing standpoint. To file a terminal disclaimer all that is needed is to file a PTO/SB/26 form stating that the patents are commonly owned at the period of time associated with the later filed application is the same as the first filed application.
  3. Amending the claims is another way to overcome a non-statutory double patenting rejection. A similar process can be used as discussed above with the statutory double patenting rejection.