Patent Term Extension (PTE): A Practical Guide for Pharma and Medical Device Patents

“The purpose of patent term extension is to place the patent owner in the position it would have been but for regulatory delay.”— Legislative history of 35 U.S.C. § 156 (Hatch–Waxman Act)

One of the most common assumptions about patents is that they last 20 years full stop. While that is broadly true, it is not the full story. In reality, certain legal mechanisms exist that can extend the effective life of a patent when time is lost due to mandatory pre-market regulatory approvals following grant. This is particularly relevant for patents covering regulated products such as pharmaceuticals and medical devices. This is where the concept of Patent Term Extension (PTE) comes into play.

Patent Term Extension is a statutory remedy designed to compensate patentees for time lost due to circumstances beyond their control. It plays a crucial role in industries such as pharmaceuticals, biotechnology, and medical devices, where years of regulatory review can significantly erode a patent’s commercial value.

Let’s unpack how PTE works, why it exists, and what inventors and businesses need to know.

Why Patent Term Extension exists: A brief historical context

The original idea behind the patent system was simple: grant inventors a limited monopoly in exchange for public disclosure of their invention. However, as technologies became more complex particularly in life sciences, it became clear that a fixed 20-year term was often insufficient.

For example, a pharmaceutical patent might be filed early in drug development, but the product could spend 10–12 years in clinical trials and regulatory review before reaching the market. By then, much of the patent term is already gone.

To address this imbalance, jurisdictions introduced term restoration mechanisms:

• United States: Patent Term Extension under 35 U.S.C. §156
• Europe: Supplementary Protection Certificates (SPCs)
• Japan and Korea: Regulatory-based patent term extensions

India, notably, does not provide patent term extension, which remains a critical policy debate in pharmaceutical patenting.

Patent Term Extension vs. Patent Term Adjustment

Before going further, it’s important to distinguish two often-confused concepts:

• Patent Term Adjustment (PTA): Compensates for patent office delays during examination (e.g., USPTO delays).
• Patent Term Extension (PTE): Compensates for regulatory delays after the patent is granted.

This blog focuses on PTE, which applies only in specific circumstances and to specific types of inventions.

How Patent Term Extension works (U.S. Perspective)

In the United States, PTE is primarily available for patents covering:

• Human or veterinary drugs
• Biological products
• Medical devices
• Food or color additives

The extension is granted to compensate for time lost during FDA regulatory review.

Patent Term Extension requirements

For drug-related patents, the following criteria must be satisfied for eligibility:

1. The patent must claim the product, a method of using the product, or a method of manufacturing the product.
2. The patent term has not yet expired.
3. The patent term has not been previously extended.
4. The application for PTE must be submitted by the patent owner or its agent.
5. The product must have been subject to a regulatory review period prior to commercial marketing or use.
6. The product must have received FDA permission for commercial marketing or use, and this approval must be the first such permission under the relevant statutory provision.
7. No other patent term may have been extended for the same regulatory review period for the product.

The PTE application must be filed within 60 days of FDA approval, a non-extendable statutory deadline. Missing this deadline can result in a permanent loss of the right to PTE.

Determining PTE eligibility and length

The USPTO and FDA share responsibilities in determining eligibility and the length of PTE:

• The USPTO first checks the application for formality compliance and confirms whether the patent itself is eligible.
• The FDA then verifies that:
  1. The product underwent a regulatory review period prior to approval.
  2. The FDA approval was the first permitted commercial marketing or use.
  3. The PTE application was filed within the 60-day statutory window.

Once the FDA confirms these points, it calculates the regulatory review period and publishes this determination in the Federal Register.

Third parties can intervene during a 60-day window to request revisions of the regulatory review period calculation. Additionally, a 180-day period exists for due diligence petitions, which allege that the applicant did not act diligently during regulatory review. The FDA resolves these petitions and hearings before issuing its final determination.

Patent Term Extension Calculation

After receiving the FDA’s final determination, the USPTO calculates the PTE using a statutorily defined formula:

PTE=RRP-PGRRP-DD-1/2(TP-PGTP)

Where:

• RRP = Total number of days in the regulatory review period, as determined by the FDA
• PGRRP = Days of RRP that occurred on or before the patent issue date
• DD = Days where the applicant did not act with due diligence (typically zero if no due diligence petition exists)
• TP = Drug testing phase
• PGTP = Days of TP occurring on or before patent issue date

Limitations on PTE

• Maximum extension: 5 years
• Total post-approval patent life: Cannot exceed 14 years from the date of FDA approval

This formula ensures that PTE compensates for regulatory delay without exceeding policy limits designed to balance public access and inventor incentives.

Example: Pharmaceutical patent

Imagine a pharmaceutical company files a patent in 2005 for a new cancer drug. The drug receives FDA approval only in 2017 after extensive trials.

• Patent expiry without extension: 2025
• Time lost in FDA review: ~12 years
• Granted PTE: 5 years (statutory cap)

New expiry date: 2030

This extension can be worth hundreds of millions of dollars, especially for blockbuster drugs.

Important case law:

Courts have consistently emphasized that Patent Term Extension is a statutory remedy that must be applied strictly and narrowly. In Merck & Co. v. Kessler, the Federal Circuit clarified how regulatory review periods are calculated and confirmed that PTE is granted on a product-specific basis. In Glaxo Operations UK Ltd. v. Quigg, the court reinforced that PTE is an exception to the standard patent term and must conform exactly to statutory limits, including eligibility requirements and extension caps.

Common pitfalls inventors should watch for

Patent Term Extension is powerful, but easy to lose if handled carelessly:

• Missing the 60-day filing deadline
• Extending the wrong patent in a patent family
• Misalignment between the approved product and patent claims
• Assuming PTE is automatic

From a strategic standpoint, patent drafting should anticipate future regulatory approval, especially for pharma and biotech inventions.

No PTE in India

India currently does not allow patent term extension, even for pharmaceuticals. The Indian Patents Act strictly limits patent life to 20 years, citing public health and access concerns.

This often leads multinational companies to rely heavily on SPCs in Europe and PTE in the U.S., while using alternative strategies such as formulation patents or process improvements in India.

Patent Term Extension is not merely a legal technicality; it is a critical commercial lifeline for regulated industries. It reflects the law’s attempt to balance innovation incentives with public interest, ensuring that inventors receive a fair opportunity to commercialize their inventions.

For inventors, startups, and IP professionals, understanding PTE is essential for long-term patent portfolio planning. A well-timed extension can dramatically alter the value of a patent while a missed opportunity can permanently shorten its life.

As with most advanced patent strategies, the key lies in early planning, precise drafting, and procedural discipline. In the world of patents, time is not just money it is the patent itself.