Legal Definitions - terminal disclaimer

A terminal disclaimer is a legal statement filed with a patent office by a patent applicant or owner. Its purpose is to limit the term of a patent or patent application so that it expires on the same date as an earlier, related patent. This action is typically taken to resolve an issue known as "obviousness-type double patenting."

Obviousness-type double patenting occurs when an inventor or company seeks to obtain a second patent for an invention that is not significantly different from, or is an obvious variation of, an invention already claimed in an earlier patent or application by the same inventor or company. Without a terminal disclaimer, granting such a second patent could improperly extend the period of exclusive rights for essentially the same invention. By filing a terminal disclaimer, the applicant agrees to ensure that both patents are commonly owned and expire simultaneously, preventing this undue extension of patent protection.

• Example 1: Software Development

  A software company develops and patents a unique data compression algorithm, which we'll call Patent A. A few years later, the same company develops a slightly optimized version of that algorithm, specifically tailored for mobile devices, and applies for a new patent, Patent B. The patent examiner determines that the mobile-specific algorithm in Patent B is an obvious variation of the original algorithm in Patent A, leading to an obviousness-type double patenting rejection. To overcome this rejection and secure Patent B, the company files a terminal disclaimer, agreeing that Patent B will expire on the same date as Patent A and both patents will remain under the company's ownership. This ensures they don't get an extended monopoly for what is essentially the same core invention.

• Example 2: Pharmaceutical Innovation

  A pharmaceutical company obtains a patent for a novel chemical compound that shows promise in treating a certain disease, referred to as Patent A. Subsequently, the company discovers a specific crystalline form of that same compound that significantly improves its stability and bioavailability, and they apply for a new patent, Patent B, covering this crystalline form. The patent office might reject Patent B on the grounds of obviousness-type double patenting, arguing that the crystalline form is an obvious derivative of the original compound. To proceed with the grant of Patent B, the pharmaceutical company files a terminal disclaimer, legally binding Patent B to expire concurrently with Patent A and ensuring both are commonly owned. This prevents them from having two separate patent terms for closely related aspects of the same drug.

• Example 3: Mechanical Engineering

  An inventor patents a new type of gear mechanism for bicycles, Patent A. Later, the same inventor develops a specific housing design for that gear mechanism that offers improved weather resistance and applies for a separate patent, Patent B. The patent examiner issues an obviousness-type double patenting rejection, stating that the housing design, while new, is an obvious adaptation for the previously patented gear mechanism. To overcome this rejection and obtain Patent B, the inventor files a terminal disclaimer. This disclaimer ensures that Patent B will expire on the same date as Patent A and that both patents will be commonly owned, preventing an extended period of exclusivity for what is considered a non-inventive improvement of the original invention.