The term of a U.S. Patent is, with certain exceptions, 20 years from the filing or priority date of the patent application. Section 154(b) of the Patent Act requires the USPTO to extend the term of a patent if the USPTO did not act promptly on the patent application while the application was pending. For example, if the USPTO fails to take certain actions within required time periods (such as issue a patent within 4 months of the date of payment of an issue fee), then the patent must be extended to account for the delay. (35 USC 154(b)(1)(A).) In addition, if the USPTO’s delay causes a patent application to pend for more than 3 years, the USPTO must add one day to the term of the patent to account for each day of the delay. (35 USC 154(b)(1)(B).)
In practice, if delays occurred under both the first clause (A) and the second clause (B) of Section 154(b)(1), the USPTO has reduced the period of patent term extension under clause B by the amount granted under clause A. A new Federal Circuit case says that this practice short-changed patent applicants. In Wyeth v. Kappos (Fed. Cir. Jan. 7, 2010), the Federal Circuit held that if an “A” delay and a “B” delay occur on different days, then there is no overlap, and the USPTO must extend the term of the patent to account for both periods of delay.