Patent Expiration Dates — Understanding Delays and Adjustments
What is a Patent Term?
The patent term is defined as the maximum amount of time a patent can be kept in force. It is commonly indicated in years, beginning from the effective filing date of the patent application.
The patent term grants the patent owner an exclusive monopoly for the duration of the term, and it is critical to pay close attention to the calculation of the patent term in order to exercise such rights.
For all patent applications submitted after June 8, 1995, the life of a patent in the United States is 20 years from the earliest or effective filing date (or priority date) when the invention was submitted to the patent office. The earliest filing date can be the date when the invention was primarily submitted as a PCT application in the WIPO or as a non-provisional application in the USPTO.
For all patent applications submitted before June 8, 1995, the patent term is calculated considering 17 years from the grant date or 20 years from the earliest or effective filing date, whichever is greater. As of March 2022, there are 778 alive US patents that were filed before June 8, 1995. All these patents were granted in the last 17 years (i.e., after March 2005) and are, therefore, alive.
However, the patent term is not exactly 20 years or 17 years in most cases due to certain factors explained below. Therefore, merely adding these years to the effective filing date does not anticipate an expiry date of the patent. Due to the additional factors, the USPTO has provided certain codes that help calculate an accurate expiry date.
Patent Term Adjustment
As per 35 USC 154 (b), calculating an extension in the term of a US patent is known as Patent Term Adjustment (PTA). The calculated PTA is added to the granted US patent’s 20-year term to anticipate the expiration date of the patent. Its goal is to make up for delays caused by the USPTO during the prosecution of a patent application.
Patent Term Delays*
The delays may be caused by the USPTO as well as the applicant, for example:
- A delayed answer to a patent application request.
- Taking more than three years to review a patent application.
- Delays caused by a confidentiality order or an appeal.
*All delays are calculated in days.
‘A’ Delay: When the USPTO fails to respond within the time frame specified, it is referred to as an ‘A’ delay. The USPTO is required to issue the First Office Action within 14 months after the application’s submission. All additional office actions must be given within four months of receiving a response from an applicant.
‘A’ delay = Date of issuance of office Action — (Date of receipt of applicant response + 4/14 Months)
‘B’ Delay: The USPTO anticipates that an application will take three years to prosecute, or three years from the date of filing to the date of issuance of the patent. If the application is not prosecuted within this time frame, ‘B’ delay is imposed. If no RCE (Request For Continued Examination) is made before the three-year deadline, a ‘B’ delay is assessed. If an RCE is submitted after the three-year term, the ‘B’ delay is calculated up to the day the RCE is filed.
‘B’ delay = Date of issue of Patent/filing of first RCE — (Date of filing of application + 3 years)
‘C’ Delay: Delays induced by PTAB appeals, interferences, or secrecy orders can be extended using the ‘C’ delay.
Applicant delay: Applicant delay occurs when the applicant fails to react to the examiner’s office action within three months after receiving it. Examples of applicant delay include:
(1) filing a response to a USPTO action or request more than 3 months after the mailing date (even if the period for responding without fees is shorter, e.g., notices to file missing parts and restriction requirements, and regardless of whether the USPTO action is defective);
(2) filing supplemental replies (including, in some cases, an Information Disclosure Statement); and
(3) filing of a supplemental reply (including, in some cases, an Information Disclosure Statement).
Overlapping Delays: The time of any adjustment allowed shall not exceed the actual number of days the patent’s issuance was delayed, to the extended periods of ‘A’, ‘B’, and/or ‘C’ delay overlap. Double-counting is forbidden when computing USPTO delays. Thus, overlapping delays must be deducted from the sum of the ‘A’, ‘B’, and ‘C’ Delays.
PTO data and computations are available through Public PAIR and are also stated in the Issue Notification paper. If there are any differences in the PTA calculation, the applicant can contact the patent office within 2 months (extendable to 5 months) following the patent’s issue, and if that does not satisfy them, they can launch civil action in the district court within 180 days.
The following equation calculates the total PTA adjustment (in days):
Total PTA (number of days) = ‘A’ delay + ‘B’ Delay + ‘C’ Delay — Applicant Delay — Overlap
PTA=0, if applicant delay equals or exceeds PTO delays.
The USPTO’s Public PAIR provides the above delays and the calculation of total PTA, as shown in the screenshot below:
Further factors that directly impact the expiration date are:
I. Domestic benefit;
II. Terminal Disclaimer; and
III. Maintenance Fee.
I. Domestic benefit: A domestic benefit is a benefit of claiming priority from an already-filed patent application. The USPTO allows filing a continuing patent application (Continuation, Continuation-in-part and divisional) which claims the priority date of the parent application and therefore does not have a term starting from it’s filing date but from the earliest filing date of the parent application.
II. Terminal Disclaimer: A terminal disclaimer is a declaration for shortening the life of a patent when it repeats the claims of a patent that expires sooner. It is mostly filed in response to a double patenting rejection from the USPTO.
In other words, when a terminal disclaimer is submitted in a pending application to avoid a non-statutory double patenting rejection, the applicant declares that the issuing patent will expire on the same day as the previously issued patent. Therefore, while calculating an expiry date of a patent, it is important to check the presence of a terminal disclaimer being filed during office action.
Patent Maintenance Fees
According to US patent law, annuities or maintenance fees must be paid on a regular basis for the patent to remain enforceable during its term. If the fee is not paid before any deadline, the patent gets lapsed on the last day of fee payment. The regular intervals for utility patents in the US are depicted here:
According to 35 U.S.C. 41(b), maintenance costs are to be paid in regular intervals of 3.5 years after grant, 7.5 years after grant, and 11.5 years after grant. A window of six months is provided to pay the maintenance fee, and an additional window of 6 months (called a grace period) is provided to pay the maintenance fee with an added surcharge. If the fee is not paid within the grace period, the patent expires on the last day of the grace period.
Patent Expiry Date Calculation
Now that we have talked about all the factors that affect the patent’s term, let’s see how to calculate the expiry date of a patent. The following flow chart depicts the process of calculating the expiry date of a utility patent.
Patent X: Say you want to find the expiration date of a patent. Let’s call it Patent X.
Domestic Benefit (Continuation, CIP, Divisional)?: Check if Patent X is a continuation of, continuation-in-part of, or a divisional of another patent application.
If the Patent X is not a continuation of, continuation-in-part of, or a divisional of another patent, then consider the earliest filing date of the non-provisional application.
In case, Patent X is a continuation of, continuation-in-part of, or a divisional of another patent, then consider the earliest filing date of the Parent application. Repeat this step until you find the earliest filed patent in the family.
Maintenance Fees Paid?: After finding the earliest filing date of Patent X, check whether the latest maintenance fees have been paid at the USPTO portal or not. The time effective time period for paying the maintenance fees is 3.5 years, 7.5 years, and 11.5 years from the patent grant date.
In case the latest maintenance fees have been paid, then add 20 years to the earliest filing date. In case the latest maintenance fees have not been paid, then check whether the payment window is open or not. If the payment window is open, add 20 years to the earliest filing date.
If the payment window is closed, then check the latest date of payment. This date will be considered the final expiry date.
Check for the terminal disclaimer in the Image File Wrapper under the USPTO Public Pair.
In case the terminal disclaimer has been filed for Patent X, then find the parent patent (Patent Y) mentioned in the terminal disclaimer. Upon finding the Patent Y, repeat the above steps for Patent Y to check the patent’s expiry date.
In case the terminal disclaimer has not been filed for Patent X, then calculate the total Patent Term Adjustments.
Patent Term Adjustment: If the patent does not have a terminal disclaimer, identify the total patent term adjustments for the patent. The PTA calculations are explained above, and can also be found in the Public Pair.
Once, the number of days in PTA are identified, they are added to the 20 years of the patent term, resulting in the final expiry date.
Case- I: Consider a patent X which is filed on 1 Jan 2000 and granted on 1 Jan 2003.
*Note, that the patent has no terminal disclaimer and continuation.
- First, add 20 years to the effective filing date of the patent X, i.e., 20 years + 1 Jan 2000 = 1 Jan 2020
- Identify the PTA adjustments (available on USPTO PUBLIC PAIR), e.g. considering the total PTA = 100 days.
- Expiry date of patent X = Effective filing date of the patent X (1 Jan 2000) + 20 years + PTA adjustments (100 days).
- Expiry date = 10 April 2020.
Case — II (with domestic benefit): Let’s assume that a patent A is filed on 1 Jan 2000, and granted on 1 Jan 2003.
*Note, patent A is a continuation of Patent B which is further a continuation of Patent C.
- Check the effective filing date of patent B which is 1 March 1999, and the effective filing date of patent C which is 20 April 1998. Finalize the earliest filing date as 20 April 1998.
- Total PTA adjustments = 100 days.
- In such a case, patent C’s effective filing date is considered (20 April 1998) for the expiry date calculation.
- The expiry date of patent A = effective filing date of patent C (20 April 1998) + 20 years + PTA adjustments (100 days).
- The expiry date of patent A = 29 July 2018.
Case — III (with a terminal disclaimer): Consider a patent X on which the terminal disclaimer if filed. Consider the effective filing date of the patent X to be 1 Jan 2000 and granted on 1 Jan 2003.
*Note, that patent Y is mentioned in the terminal disclaimer of patent X.
- Consider the effective filing date of the patent Y which is 20 December 1998
- Total PTA adjustments = 100 days.
- In such a case, the expiry date of patent X is calculated on the effective filing date of patent Y.
- The expiry date of patent X = Effective filing date of the patent Y (20 December 1998) + 20 years + PTA adjustments (100 days).
- The expiry date of patent X = 30 March 2019.
The patent’s expiration date is generally considered to be 20 years from the earliest filing date. But this consideration almost never yields the most accurate date of expiration. In situations where data precision is imperative, for example, while calculating patent infringement damages, the factors discussed above carry weight for calculating an accurate date of expiration.
Also, read our article “Is your patent expiring? Here’s how to calculate patent expiration dates!”
Disclaimer: This article and its substance is not a legal opinion and should not be considered legal advice. Copperpod IP encourages readers to seek legal opinion from a practicing patent attorney (or ask us to recommend one!) for calculating patent expiration dates on a case-by-case basis.