May 27, 2020

Strategic Considerations for Seeking Patent Term Extension (PTE) and its Scope for Drug Products

Life science companies developing new therapeutics – both small molecule and biologic – know that obtaining long patent term for their products is a key driver of valuation and revenue. A particular challenge in this respect is minimizing the loss of patent term during drug development. Fierce competition in the marketplace often requires that innovators patent their drug products as early as possible in the development process, but because the clock on a United States (patent’s lifespan starts running the moment it is filed, years of valuable patent term are often lost as a product navigates the regulatory approval process. An important method to mitigate these losses can be found in the Patent Term Extension (“PTE”) provisions of 35 U.S.C § 156, which provide statutory compensation for the substantial time and resources expended by an innovator to bring a new drug to market. In a nutshell, PTE restores a portion of the patent term, up to five years, that is lost during the period a new drug or medicinal product is awaiting pre-market regulatory approval in the U.S.. When a new chemical entity (“NCE”) – either a small molecule or a biologic – is approved by FDA as a therapeutic, a patent claiming either the NCE or its method of use may be entitled to PTE.

There are several important factors innovators should consider when seeking PTE. For example, the Federal Circuit’s recent decision in Biogen v. Banner highlights the coverage of PTE as it relates to other, likely competitor, compounds.[1] Understanding the mechanics of PTE can be of critical importance to maximize the impact and coverage of PTE, and to protect against competition.

What is the permissible amount of PTE term?

The maximum amount of PTE possible is five years. The amount of PTE available is generally derived from two key time periods: the “testing period,” the time between the filing of an Investigational New Drug (IND) application and the filing of a New Drug Application (NDA); and the “approval period,” the time between NDA filing and FDA approval. PTE is generally calculated, based on the regulatory review period for the approved product, following the formula:

PTE = (1⁄2 x Testing Phase) + Approval Phase

It is important to note that: (a) any time during which the applicant did not act with due diligence and any time elapsed before the patent issued will be excluded from the PTE calculation; and (b) the term of any patent extended in this manner cannot exceed 14 years following the approval date.

How and when is PTE requested?

The PTE application must be filed with the USPTO within 60 days of FDA approval.

The requirements for submitting a PTE application are fully set forth in 35 U.S.C. § 156(d)(1), and generally require, among other things, the identity of the approved product; the identity of the patent for which an extension is being sought and the identity of each claim in the patent that covers the approved product; information to enable the USPTO to determine the eligibility of the patent for extension; and a brief description of the activities undertaken by the applicant during the applicable regulatory review period with respect to the approved product and the significant dates applicable to such activities.

Can PTE be applied to more than one patent covering an approved drug product?

No. While there is no limit as to how many patents a company may designate as a potential PTE recipient, only one patent can be ultimately selected for the PTE term. This means that while only one patent may receive PTE, an innovator can push off the important tactical decision of which patent to choose by filing multiple PTE requests in the 60-day period following approval.

What is the scope of PTE?

PTE applies to the active ingredient that is administered as part of the drug product, which must be present in the particular dosage form applied to the patient. This active ingredient must also be the basis for the regulatory approval and must be designated as such in the approved product’s label. Note that PTE is not available to drug products that were previously approved and/or subject to regulatory review. 

An innovator seeking PTE should therefore ensure that the active ingredient: (1) is claimed in a patent to which PTE is sought; (2) is present in the drug product as administered (and approved); (3) is named on the drug label as the active ingredient; and (4) was not previously approved or subject to regulatory review.

For patents covering either the drug product or methods for its use, the PTE is limited to the use(s) that have been approved by the FDA for the product. Any PTE of the approved drug product will not cover later-obtained indications. For patents directed to the manufacturing of a drug product, any PTE will be limited to the manufacturing method used to make the product under regulatory review.

What is the “approved drug” that is protected under PTE?

According to the plain language of 35 U.S.C. §156(f)(2), the “drug product” protected under PTE is “the active ingredient” of a new drug “including any salt or ester of the active ingredient, as a single entity or in combination with another active ingredient.” Thus, PTE can be used to protect other salt and ester forms of the active ingredient in a drug product. 

How does PTE apply in practice to protect against generic and follow-on competition?

When an innovator seeks to use PTE to preclude the market entry of generic and/or follow-on products, all of the factors discussed above will play a role in determining the success of this strategy. Five potential scenarios include:

  1. Same active ingredient – If a competitor were to seek approval of a drug product containing the exact same active ingredient used by the innovator for the same indication, PTE may preclude market entry.
  2. Different salt – If a competitor were to seek approval of a drug product containing a different or novel salt form of the same active ingredient used by the innovator for the same indication, PTE may preclude market entry.
  3. Ester If a competitor were to seek approval of a drug product containing an ester form of the same active ingredient used by the innovator for the same indication, PTE may preclude market entry.
  4. De-esterified form or different ester If the innovator has attained approval for an ester form of a particular drug molecule and a competitor seeks approval of the de-esterified (free) form of that same drug molecule, PTE may not preclude market entry regardless of the indication sought or the clinical data cited in the competitor’s application.[2] Further, the competitor may, under some circumstances, be able to obtain PTE on its own active ingredient.
  5. Different indication If a competitor seeks approval of a drug product for a new indication that was not previously the subject of regulatory review, PTE may not preclude market entry regardless of how the competitor’s active ingredient compares to that of the innovator.

To help life sciences companies maximize regulatory and patent exclusivity, Goodwin patent prosecution partner Theresa Kavanaugh crafts strategic considerations specifically for companies close to regulatory approval or in the late stages of development of a therapeutic small molecule or biologic. Look for additional insights from our life sciences team in your email or on

[1] Biogen Int’l GMBH v. Banner Life Sciences LLC, No. 2020-1373, slip. op. (Fed. Cir. Apr. 21, 2020)

[2] See Biogen v. Banner, Slip Op. at 9.