United States: How Is Patent Term Extension Calculated For A Reissued Patent?

The Patent Term Extension (PTE) provisions of 35 U.S.C. 256 were enacted as part of the Drug Price Competition and Patent Term Restoration Act of 1984. PTE partially compensates pharmaceutical patent owners for the time they are not able to enjoy commercial market exclusivity because their products are not yet approved by the U.S. Food and Drug Administration (FDA). The length of a PTE award depends on how much time was spent under FDA review after the patent was issued. Current ANDA litigation involving Merck's BRIDION^® product asks which issue date is used when PTE is obtained for a reissued patent. Using the original issue date — as was done here — will maximize a PTE award, while using the reissued date could eviscerate PTE.

The Patent Term Extension Statute

The basic PTE provision is set forth in § 156(a), which provides in part:

(a) The term of a patent which claims a product, a method of using a product, or a method of manufacturing a product shall be extended in accordance with this section from the original expiration date of the patent, which shall include any patent term adjustment granted under section 154(b), if — ...

(4) the product has been subject to a regulatory review period before its commercial marketing or use ....

The statutory language at issue in the BRIDION^® case is found in § 156(c), which provides in part (emphasis added):

(c) The term of a patent eligible for extension under subsection (a) shall be extended by the time equal to the regulatory review period for the approved product which period occurs after the date the patent is issued, except that —

Usually "the date the patent is issued" is clear — and clearly printed on the face of the patent. The BRIDION^® ANDA litigation raises the question of which date should be used for a reissued patent: the date the patent was first issued or the date the patent was reissued?

The Reissue Process

A patent owner can request "reissue" of a granted patent that, "through error, [is] deemed wholly or partly inoperative or invalid, by reason of a defective specification or drawing, or by reason of the patentee claiming more or less than he had a right to claim in the patent." See 35 U.S.C. § 282. Obtaining a reissued patent requires "surrender" of the original patent. The term of a reissued patent is "the unexpired part of the term of the original patent." By statute, "every reissued patent shall have the same effect and operation in law, on the trial of actions for causes thereafter arising, as if the same had been originally granted."

Merck's Reissued Patent and PTE Application

U.S. Patent No. 6,670,340 was issued on December 30, 2003. Merck sought a reissue of the patent in 2012, and the patent was reissued on January 26, 2014, as RE44,733. After BRIDION^® was approved in late 2015, Merck sought PTE for RE44,733. Merck used the issue date of the original patent in its PTE calculations, and the USPTO awarded PTE accordingly.

The Reissued Patent Issue Date Issue

When Merck asserted RE44,733 in ANDA litigation, the ANDA defendants challenged the issue date used in the PTE calculation. Using the issue date of the original patent meant the entire regulatory review period occurred after the patent was issued, so the patent was awarded a maximum PTE award of five years. If the reissued date had been used, the PTE award would have been a fraction of that length — and the patent would have expired by now.

The district court sided with Merck, based on its interpretation of the PTE and reissues statutes, and giving deference to what it understood is the USPTO's position. In that regard, the current edition of MPEP § 2766 directly addresses this issue and states:

According to the ANDA defendants, this guidance was not promulgated until 2022 (after the underlying ANDA litigation commenced). Their appeal to the Federal Circuit is pending.

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