Patenting newly developed drug products is the life’s blood of a branded pharmaceutical company. Without new patents, there is little room for economic growth or stability; thus the ability to obtain patents on new drug products is crucial for maintaining market share in a highly competitive industry and for fostering further research and development. The grant of a patent on any new drug product brings along with it, or should, an exclusionary right over competing drug developers. Yet far too often, the United States Patent and Trademark Office (“PTO”) grants a patent to a pharmaceutical company on a drug before the Food and Drug Administration (“FDA”) approves the newly developed drug for commercial marketing or use. When this happens, pharmaceutical companies are unable to take full advantage of their patent exclusivity, at least during the FDA review period. Because the clock ticks against the period of patent exclusivity during the period of FDA review of the drug, it is imperative that the patent owner fully utilize the provisions of the Patent Statute to extend a drug’s patent term whenever this is possible.

This article highlights some of the key steps leading to patent term extensions for human drug products patented after Sept. 24, 1984. This article does not apply to drug products that are subject to the Virus-Serum Toxin Act or are directed to non-human use.

When all or part of a patent term is or will be depleted by prolonged FDA review of the drug product, there is a way to recover a portion of the period lost during FDA review, up to a maximum of five years. Because it is the PTO that grants a patent in the first place, extending the period of patent protection involves applying to the PTO to obtain a patent term extension. The application must specifically request a time period for which extension is sought and state how the time period was calculated. It must be filed before the patent expires and must be filed within 60 days of the grant of FDA approval for the drug product. It also must confirm that the FDA approval is the first approval received for the drug product’s commercial marketing or use.

If granted, the patent term extension will begin from the original expiration date of the patent or any earlier date set by terminal disclaimer. Generally, if the facts provided to the PTO are fully developed and the patent owner is diligent during the process of FDA review, the length of the patent term extension can be calculated to be equal to the length of the FDA review period of the drug product.

Determine the Length of FDA Review

The PTO’s determination of the length of any patent term extension is predicated principally on the length of the FDA review period for a drug product (which is composed of both the testing and approval phases of a new drug product). However, it is not the PTO that determines the length of the extension awarded from the FDA review period. This is done by the FDA itself, which determines the length of the review period by reviewing its own official records for the drug product under consideration and by reviewing the information provided to the PTO by the patent owner applying for patent term extension. Fully and accurately capturing the length of the period of review is critical to obtaining a period of patent extension commensurate with the investment in the drug product. Thus, the application to the PTO for patent term extension must provide the necessary information to assist the FDA in accurately determining the length of its review period, including, for example, such critical information as the patent expiration date because, as noted above, the request for extension must be filed before the patent expires.

Evaluating the length of the review period is challenging because the length can be reduced by charging any delay in the review process against the patent owner if the patent owner failed to act with “due diligence” during the process of FDA review. Obviously, any time charged against the patent owner will reduce the length of the patent term extension and will harm the economic interests of the patent owner. To avoid this, it is imperative to include in the application for patent term extension a description of pertinent facts, such as significant activities the applicant has undertaken during the FDA review period and the significant dates associated with these activities, even if they involve only communications between the applicant and FDA during the FDA review period. It cannot be assumed that the FDA will take these facts into account without having been specifically led to them. So the application must include, at a minimum:

  • The dates and nature of submissions of new data to the FDA
  • Communications between the applicant and the FDA regarding the proper protocols for product testing 
  • Communications between the applicant and the FDA attempting to define the particular requirements for pre-marketing approval for the applicant’s product 
  • A statement confirming the patent owner’s knowledge and understanding of the duty to disclose material information to the PTO regarding its application for a patent term extension 
  • Copies of the written documents that contain the content of the disclosed information

Making this type of information available in the application process will help to lead the FDA, and then the PTO, to the proper conclusion as to the needed length of patent extension. Once the FDA reaches its conclusions as to the length of the review period, it forwards it to the PTO and publishes it in the Federal Register (along with the relevant dates on which the determination was based).

Any party that may be adversely affected by the grant of a patent term extension may file a petition, within 180 days after the FDA review period is published in the Federal Register, requesting a determination of whether the patent owner acted with due diligence during the FDA review period. If the patent owner has provided the complete information within its application, it will help to prevent an adverse ruling by the FDA if any petition is filed.

For a patent term extension to be granted, there must be at least one claim of the patent that covers the commercial drug product. Thus, the application must detail how the claim or claims read on the approved drug product, the method of using the approved drug product, or the method of manufacturing the approved drug product.

Once a patent is found eligible for patent term extension, the PTO sets forth the extension period in a Notice of Final Determination (“Notice”) mailed to the applicant and usually provides a onemonth period in which the applicant can make a request for reconsideration of the PTO’s determination.

Interim Extensions

As noted above, an application for patent term extension must be filed before the patent expires and after FDA approval is obtained. Yet in some cases, the patent term will expire before FDA approval can be obtained. In this case, the patent owner may file for interim one-year extensions with the PTO, usually not to exceed a total of four years. Once the FDA issues its formal approval for the commercial product, however, the application for an interim extension must be converted to an application requesting extension of the patent term.

The interim extension will terminate 60 days after FDA approval is granted. Even while a request for a patent term extension is pending, there may be a need to request an interim extension. This is possible only (1) if the FDA already has issued its approval, and (2) if the original patent term would expire before a determination can be made on the underlying application for patent term extension. As with the pre-FDA approval requests for interim extension, a grant of interim extension in these circumstances is only for one year, although additional interim extensions may be available if more time is necessary.

This post-FDA approval interim extension request is best filed three months prior to the patent’s expiration date.

As with the request for a patent term extension, any request for an interim extension must be made prior to the expiration of the patent.


Patents of newly developed drugs are critical to a pharmaceutical company’s financial success, as well as future research and development prospects. Knowing how to extend a drug product’s patent term to compensate for reduction of the patent term because of lengthy FDA review may be essential to a pharmaceutical company’s strategic plan.