Understanding Terminal Disclaimers in U.S. Patent Practice: A Practical Guide

When prosecuting a U.S. patent application, few surprises are more common—and more confusing to inventors—than receiving an obviousness-type double patenting (OTDP) rejection. Fortunately, applicants often have a straightforward tool available to overcome this problem: the terminal disclaimer. Although widely used, terminal disclaimers carry real consequences. Understanding how they work and when they are appropriate is essential to managing a patent portfolio strategically.

What Is Obviousness-Type Double Patenting?

OTDP is a judicially created doctrine intended to prevent an applicant from obtaining multiple patents with claims that are not patentably distinct. In simpler terms, you cannot get two patents that cover essentially the same invention or obvious variations of each other. Without this rule, a patent owner could extend their exclusivity beyond the statutory term by filing slightly modified applications over time.

OTDP rejections typically arise between:

• A pending application and an issued patent owned by the same applicant;

• Related patents that share similar priority claims; or

• Continuations, divisionals, or CIPs where claim scope overlaps significantly.

What Is a Terminal Disclaimer?

A terminal disclaimer is a statement filed by the applicant in which they disclaim any patent term beyond the expiration date of a commonly owned patent and agree that the later-issuing patent will remain commonly owned with the earlier one. Once accepted, the USPTO withdraws the OTDP rejection.

In effect, a terminal disclaimer ties the lifespan and ownership of the two patents together. It ensures that the patentee does not gain an unjustified extension of patent protection while still permitting issuance of a second patent containing obvious variants.

Advantages of Using a Terminal Disclaimer

1. Fast and Predictable Resolution
Filing a terminal disclaimer is often the quickest way to overcome an OTDP rejection. It avoids the need for extensive argument or claim amendments and keeps the application moving toward allowance.

2. Retains Additional Claim Coverage
Instead of narrowing claims to avoid overlap, applicants can maintain broader or alternative claim sets. This is especially useful in continuations where strategic claim differentiation may be limited.

3. Cost-Effective
The USPTO fee is modest, and the process avoids the attorney time required to craft substantive responses.

Disadvantages and Strategic Costs

1. Loss of Patent Term
A terminal disclaimer cuts off any patent term extension that the later-issued patent might otherwise have earned, including Patent Term Adjustment (PTA). This can shorten protection by years.

2. Mandatory Common Ownership
A disclaimed patent must remain commonly owned with the reference patent for its entire life. This restricts licensing flexibility and can complicate corporate transactions or spin-offs.

3. Potential Enforcement Limitations
If common ownership breaks (even inadvertently), the disclaimed patent becomes unenforceable. This can create risk in joint ventures or assignments.

4. Avoids, but Doesn’t Resolve, the Underlying Similarity
The disclaimer sidesteps the OTDP issue rather than proving patentable distinction. This can matter in future litigation where defendants may argue that the patents cover essentially the same invention.

Bottom Line

Terminal disclaimers are a powerful and often practical tool for overcoming obviousness-type double patenting rejections. They deliver efficiency and preserve valuable claim scope—but at the cost of patent term and ownership flexibility. Inventors and companies should weigh these trade-offs carefully and use terminal disclaimers strategically, not reflexively.