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Continued Increase in Patent Term Extension Allowances in Singapore

21 Oct 2025

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Last year, we noted a surge in the annual Patent Term Extension (PTE) allowance rate commencing in 2022 (see www.drewnapier.com/Publications/Potential-underutilisation-of-PTE-in-Singapore). Based on data available on the IPOS website as of mid-September 2025, the uptick in the PTE allowance rate has further accelerated. PTE allowances in the first eight months of calendar year 2025 have already surpassed the PTE allowances for the full year of 2024.
 
Eligibility Requirements for PTE in Singapore
 
Pursuant to the Singapore patent provisions, minimal requirements for PTE mandate one of the following:
  • Local Examination. Where the application undergoes local examination by IPOS, PTE is not available unless: (a) the interval between the filing date and the patent grant date (excluding periods attributable to the applicant) exceeded four years; or (b) the interval between the examination request date and the patent grant date (excluding periods attributable to the applicant) exceeded two years. 
  • Supplementary Examination. Where the application undergoes Supplementary Examination by IPOS, PTE is not available unless: (a) the interval between the filing date and the patent grant date (excluding periods attributable to the applicant) exceeded four years; or (b) the patent office that granted the corresponding patent or related national phase patent extended that patent due to an unreasonable delay in its issue by that patent office.
  • Unreasonable Curtailment due to HSA Delay. Where the Singapore Health Sciences Authority (HSA) has processed an application for marketing approval for a patented pharmaceutical product, PTE is not available unless the HSA marketing application cycle time (excluding periods attributable to the applicant) exceeded two years, resulting in an unreasonable curtailment of the opportunity to exploit a patent.
Historical Statistics on PTE Allowances
 
As of mid-September 2025, the Intellectual Property Office of Singapore (IPOS) has allowed PTE for a total of 75 patents. Of these 75 patents, 60 relate to pharmaceutical or biomedical technology. The legal basis for the PTE allowances can be confirmed in 63 of the 75 patents based on the online “Patent Open Dossier” documents accessible from the IPOS website.
 
In 61 of the 63 confirmed online records, PTE requests were allowed on the basis that the interval between the examination request date and the patent grant date (excluding periods attributable to the applicant) exceeded two years. This avenue for PTE is referred to as “Type B” by IPOS, in reference to subsection (b) of Singapore Patents Rule 51A(5)(b).
 
In two of the 63 confirmed online records, PTE was allowed because the patent office that granted a corresponding patent extended the term of that corresponding patent due to an unreasonable delay in its issue by the patent office. In both of these instances: (a) the corresponding patent was issued by the U.S. Patent and Trademark Office (USPTO); (b) the corresponding patent received a Patent Term Adjustment (PTA) due to an unreasonable delay in its issue by the USPTO; and (c) the number of PTE days allowed in Singapore was identical to the number of PTA days allowed for the corresponding patent by the USPTO.
 
There are no online records documenting any PTE allowances based on the interval between the filing date and the patent grant date (excluding periods attributable to the applicant) exceeded four years. This avenue for PTE likely has never been used because most of the time interval between the filing date and the examination request date is easily attributable to the applicant. Unlike before the USPTO, Singapore patent practice permits applicants to request local examination up to 36 months after the earliest priority date (54 months for Supplementary Examination). Hence, the Type B avenue for PTE, with its requirement to exceed just two years rather than four years, is a preferable avenue for PTE.
 
There are also no online records documenting any PTE allowances based on an HSA marketing application cycle time exceeding two years. HSA marketing approval applications typically leverage the positive results received from the U.S. Food and Drug Administration (FDA) and/or the European Medicines Agency (EMA). As a result, the HSA marketing application cycle time is typically less than two years, most often in the range of 14 to 18 months.
 
Differences Between U.S. and Singapore
 
Because of differences between the patent provisions of the United States and the patent provisions of Singapore, there is a potential for U.S.-based proprietors to be unaware of their ability to extend the term of their Singapore patents. Such potential oversights are less likely for proprietors based in Europe, Japan, and China, as the patent provisions in their home jurisdictions are more similar to those of Singapore.
 
Key differences in the patent provisions between Singapore and the United States include:
  • Vocabulary Differences. Under the U.S. patent provisions, “Patent Term Adjustment” (PTA) refers to an extension of the patent term based on delays in the patent examination process, while the term “Patent Term Extension” (US-PTE) refers to extension of the patent term based on delays in obtaining regulatory approval from the FDA. In Singapore, both of these types of extensions are referred to under the same term: “Patent Term Extension” (PTE).
  • PTA is Automated by USPTO. For U.S. patents, PTA is automatically calculated by computer programs run by the USPTO. The proprietor is alerted of the number of PTA days by the USPTO via the U.S. patent’s Issue Notification Letter. The number of PTA days is also listed by the USPTO on the face of the published U.S. patent. Only when seeking US-PTE based on FDA processing delays is the proprietor required to take unilateral action to extend their U.S. patent.
  • PTE in Singapore is Not Automatic and Its Request is Time-Limited. Under the Singapore patent provisions, all types of extensions require unilateral action by the proprietor. If unilateral action is not taken by the proprietor within six months of the Singapore patent grant, for instance, PTE based on unreasonable delay in prosecution is no longer available.
 
These legal differences can lead to incorrect assumptions and a loss of potential PTE rights in Singapore. U.S.-based proprietors, for instance, could assume incorrectly that IPOS will automatically extend the Singapore patent without unilateral action by the U.S.-based proprietor. Particularly in the situation where HSA approval is still pending for a granted Singapore pharmaceutical patent, U.S.-based proprietors could decide to wait until after the HSA marketing approval before investigating the potential eligibility of their patent for PTE in Singapore. Such delay could result in the proprietor inadvertently missing the (non-extendable) six-month deadline to extend the patent due to unreasonable prosecution delay.
 
Common Calculation Errors
 
Though correctable, another challenge for proprietors is correctly calculating the days of PTE. These calculations are governed by the more than 2,300 words of the Singapore Patents Rule 51A. Of the 63 confirmed online records, about 25% were initially rejected due to the proprietor’s miscalculation of PTE days. Key calculations involve the following:
  • Interval Between. An “interval between” the examination request date and the patent grant date is calculated by excluding both the examination request date and the grant date. As an example, the interval between January 1st and January 10th would be calculated by IPOS as 8 days (e.g., excluding both the start date and the end date), rather than 9 days. Miscalculation of the interval period by one day has been the most common mistake made by proprietors seeking PTE in Singapore.
  • Two Years. As documented in online records, the two-year period employed in the most common PTE allowance is always equal to 730 days (regardless of the possibility of leap years during the prosecution of the patent).
  • Periods Attributable to the Applicant. The calculation of periods attributable to the applicant, such as the period taken by the applicant to respond to a Written Opinion, are a straightforward subtraction of a first milestone date from a second milestone date. Such calculations are often best performed using Microsoft Excel, which accounts for the differing lengths of each month and potential leap years.
 
While other IPOS fees were increased effective 01 September 2025, the fee for requesting PTE in Singapore remains the same at 950 SGD. The renewal fees for each year of a Singapore patent after the normal 20-year term, however, were increased from 1,380 SGD to 1,470 SGD.
 
As PTE typically must be requested by the proprietor within six months from the patent grant date, proprietors interested in potential PTE should seek prompt legal advice from their Singapore legal counsel regarding PTE eligibility for their recent Singapore patent grants.
 
The content in this posting is for general informational purposes only. This posting is not intended to constitute or to be relied upon as legal advice. You should consult Singapore legal counsel if you require legal advice regarding Singapore patent practice. The information and opinions expressed in this posting are those of myself and do not necessarily represent the view of my employer Drew & Napier LLC.

- Written by Patrick W. Duncan, Singapore Patent Agent and USPTO Patent Attorney at Drew & Napier LLC