Calculating US Expiry Dates - GenericsWeb

Calculating US Expiry Dates
To calculate full-term expiry of a patent in the US, use one of the two following rules:
1. For patents based on applications filed before 08/06/1995 (INID Code 22):
Add 17 years to patent issue date shown on front page of patent (INID code 45) to obtain first date
(take note of any terminal disclaimer or extension or adjustment to the patent term denoted by an
asterisk and also published below the ‘Assignee’ information (INID code 73); for reissued patents see
below). Next add 20 years to the application date of the earliest related application shown on the
front page of patent (INID codes 62 or 63) to obtain second date (note provisional applications (INID
code 60) are disregarded in the calculation). The later of these two dates is the expiry date. Add any
applicable extensions or adjustments to the patent term, and then account for any terminal
disclaimers to obtain the full-term expiry.
2. For patents based on applications filed on or after 08/06/1995 (INID Code 22):
Add 20 years to the date of the earliest related application shown on front page of patent (INID
codes 62 or 63) to obtain the expiry date (note provisional applications (INID code 60) are
disregarded in the calculation). Add any applicable extensions or adjustments to the patent term,
and then account for any terminal disclaimers to obtain the full-term expiry.
Matters affecting full-term expiry:
i. Patent Term Adjustments (PTAs) under 35 U.S.C. 154(b), see the front page image of the
document or USPTO Patent Application Information Retrieval (PAIR) available at
http://portal.uspto.gov/external/portal/pair (see Appendix 1).
ii. Terminal Disclaimers, see the front page image of the document or PAIR (see Appendix 2).
Take care with:
i. Reissued patents – inspect the front page of the reissued patent to determine the original
patent (shown under INID code 64). Calculate the expiry of the original patent as per the
above rules. The expiry of the reissued patent is identical to that of the original parent (see
Example 5).
ii. The filing, grant and earliest related application dates. Details on the front page of the
patent should be independently verified wherever possible to ensure the correct date is
obtained (see Appendix 3 and Example 9).
iii. The filing date of the patent – always look for the date at INID code 22. If the patent is a
national phase entry of a PCT, don’t use the §371 Date or §102 Date as the filing date.
iv. The ‘Related U.S. Application Data’ may be listed at INID code 60. Ensure you look for
‘Division of…’, ‘Continuation of…’, or ‘Continuation-in-part of…’ on the front page of the patent
and double-check PAIR for verification.

DISCLAMIER: All US expiry dates in GenericsWeb products are shown as the maximum full-term
expiry date as calculated manually according to our understanding of the patent term calculation
rules, and do not account for any applicable terminal disclaimer(s). The material in this guide is
intended only to provide a summary and general overview for calculating the term of patent under
current US Patent Law. It does not constitute legal advice. You should seek legal or other
professional advice before acting or relying on any of the content. In no circumstances will
GenericsWeb, its agents or employees be liable for any special, consequential or indirect loss or
damage arising from any use of or reliance on any material appearing in this guide. The information
in this guide is liable to change and we do not guarantee its currency.
In the following examples, for the sake of brevity, all the information on the front page of the patent
has already been verified and has been determined to be accurate and comprehensive by use of PAIR
(see Example 9 to understand how this verification was carried out).
Note: Date format DD/MM/YYYY is used throughout.
Example 1.
[22] = 23/03/1984, thus use Rule 1. No related application, thus use [22] filing date + 20 years =
23/03/2004.
[45] = 28/03/1989 + 17 years = 28/03/2006.
Expiry is the later of the two dates, thus full-term expiry is 28/03/2006.

Example 2.
[22] = 23/10/1996, thus use Rule 2. No related application, thus use [22] filing date + 20 years =
23/10/2016.
Thus full-term expiry is 23/10/2016.
Example 3.
[22] = 06/06/1995, thus use Rule 1. Earliest related application + 20 years = 04/08/2009.
[45] = 12/08/1997 + 17 years = 12/08/2014.
Expiry is the later of the two dates, thus full-term expiry is 12/08/2014.

Example 4.
[22] = 04/06/1996, thus use Rule 2. Earliest related application + 20 years = 04/08/2009.
Thus full-term expiry is 04/08/2009.
Example 5.
[64] = Reissue of US4943590, thus full-term expiry of USRE34712 is identical to the full-term expiry
of US4943590. To calculate the full-term expiry of US4943590, refer to the front page of the patent
directly.

[22] = 08/06/1989, thus use Rule 1. No related application, thus use [22] filing date + 20 years =
08/06/2009.
[45] = 24/07/1990 + 17 years = 24/07/2007.
Expiry is the later of the two dates, thus full-term expiry is 08/06/2009.
Example 6.

[22] = 12/12/2001, thus use Rule 2. Earliest related application + 20 years = 07/07/2020.
Note the asterisk (*) near the grant issue date [45] and the corresponding information on the front
page published below the ‘Assignee’ information (INID code 73) indicating a terminal disclaimer has
been filed as well as 0 days PTA.
Upon inspection of disclaimer information for this record in PAIR, it reveals the patent would not
extend beyond the expiration date of US6960613 (see Appendix 2). It also confirmed in PAIR that
the PTA is 0 days (see Appendix 1).
The full term expiry of US6960613 is calculated below:
[22] = 20/08/2003, thus use Rule 2. Earliest related application + 20 years = 07/07/2020.
Thus full-term expiry is 07/07/2020 plus 0 days PTA, with expiry not exceeding 07/07/2020 =
07/07/2020.

Example 7.
[22] = 10/01/2002, thus use Rule 2. Earliest related application + 20 years = 18/03/2011.
Note: ‘Related U.S. Application Data’ is listed at INID code 60.
Note there is no asterisk (*) near the grant issue date [45], however there is an asterisk on the front
page published below the ‘Assignee’ information (INID code 73) indicating PTA of 334 days is
applicable.
Upon inspection of the PTA for this record in PAIR, it is confirmed that the PTA is 334 days (see
Appendix 1).
Thus full-term expiry is 18/03/2011 plus 334 days PTA = 15/02/2012.

Example 8.
[22] = 06/02/2004, thus use Rule 2. Earliest related application + 20 years = 18/03/2011.
Note: ‘Related U.S. Application Data’ is listed at INID code 60.
Note the asterisk (*) near the grant issue date [45], and the corresponding information on the front
page published below the ‘Assignee’ information (INID code 73 indicating a terminal disclaimer has
been filed as well as indication of a PTA of 486 days.
Upon inspection of disclaimer information for this record in PAIR, it reveals the patent would not
extend beyond the expiration date of US6284471, US6790444, US7070775 or US7276239 (see
Appendix 2). It also confirmed in PAIR that the PTA is 486 days (see Appendix 1).

For the sake of brevity, the full-term expiry of the patents was calculated to be:
US6284471 = 18/03/2011
US6790444 = 11/07/2011
US7070775 = 11/07/2011
US7276239 = 18/03/2011
Thus full-term expiry is 18/03/2011 plus 486 days PTA, with expiry not exceeding 18/03/2011 =
18/03/2011.
Example 9.
Any good researcher understands the need to verify data across many sources to confidently finalise
any expiry date. A common error on the front page image of US patents is the incorrect listing of
‘Related U.S. Application Data’ (INID codes 62 or 63), for example, the earliest related application
may not be the earliest per se. Verifying the earliest related application information on every
occasion is critical to obtaining an accurate expiry date. Verification of other information (application
date, grant date, etc.) via INPADOC, PAIR, etc. is also critical.
[22] = 15/05/1998, so use Rule 2. Earliest related application + 20 years = 07/11/2017 (provisional
applications are not considered).
Thus full-term expiry is 07/11/2017. But is it?
Let’s check…

Application 08/965,922 is now patent US5972967. Inspection of this patent reveals:
This patent is a divisional of another application, namely 08/735,878 now patent US5733919.
Inspection of US5733919 reveals that it is the earliest related application in this family and thus the
earliest related application date is 23/10/1996.
Thus full-term expiry is actually = 23/10/2016.
You can also verify related application data in PAIR via the ‘Continuity Data’ tab (see Appendix 3).

Appendix 1 – Finding PTAs in PAIR.
Enter the captcha image in the PAIR welcome screen and enter the number into the search screen.
To enter a ‘Patent Number’ use format NNNNNNN or N,NNN,NNN (e.g. 5972967 or
5,972,967)
To enter an ‘Application Number’ use format NN/NNNNNN (e.g. 07/902500)
To enter a ‘Publication Number’ i.e. a published US patent application use YYYY0NNNNNN
Click on the ‘Patent Term Adjustments’ or ‘Patent Term Extensions’ tab.
Verify the number of days a patent has been adjusted for in the ‘Total PTA Adjustments’ field.

Appendix 2 – Finding Terminal Disclaimers in PAIR.
If a Terminal Disclaimer is referenced on the front page image of a document, you can consult PAIR
to find the details of the portion disclaimed.
Follow the instruction in Appendix 1 to access registry information in PAIR.
Click on the ‘Image File Wrapper’ tab, look in the ‘Document Code’ column for ‘DISQ’ (disclaimer
filing) or ‘DIST’ (disclaimer decision) or search for ‘disclaim’ on the page (note that there may be
more than one disclaimer for each patent). Inspect all of the terminal disclaimers and note all the
patent and/or application numbers referenced (an extracted example is pasted below). The
maximum full-term expiry of the patent is equal to the earliest expiry of the referenced patents.
Note: the ‘Image File Wrapper’ tab is not always freely available in PAIR, but you can order the file
wrapper by clicking ‘Order Certified File Wrapper’ at the top of the page.
Terminal Disclaimers get complicated when s156 patent term extensions (PTEs) are applied, consult
http://en.wikipedia.org/wiki/Term_of_patent_in_the_United_States#Terminal_disclaimer for
reference.

Appendix 3 – Verifying data in PAIR.
Follow the instruction in Appendix 1 to access registry information in PAIR.
You will be directed to the ‘Application Data’ tab. Here you can verify the filing date [22] (‘Filing or
371(c) Date’) and the grant issue date [45] (‘Issue Date of Patent’). Again, take special care with
the ‘Filing or 371(c) Date’ to ensure you are verifying and obtaining the filing date of the patent and
not the 371(c) national phase receipt date.
Verification of the related applications is done via the ‘Continuity Data’ tab. It details both parent
continuity data (information on what the patent is a continuation/division/continuation-in-part of) as
well as child continuity data (information on what patents claim the benefit of the application).
Drill down through the continuation history to verify the earliest related application date.