Terminal Disclaimer Does Not Negate Hatch-Waxman Term Extension

Merck v. HI-TECH (Fed. Cir. 2007).

During prosecution of its patent application covering TRUSOPT, Merck filed a terminal disclaimer to voluntarily cut-short the duration of its patent’s validity.  The terminal disclaimer helped Merck overcome some of its own prior-art that might have obviated the invention.  Later, because of delays in FDA regulatory approval, Merck was able to tack-on an additional 3+ years — moving the expiry date from Dec ’04 to Apr ’08.

HI-TECH filed a Paragraph IV certification requesting approval for a generic version of the glaucoma treatment and asserting that Merck’s patent was expired and invalid. The district court dismissed the case — holding that the Hatch-Waxman term-extension was not canceled by the terminal disclaimer.

Law: 35 USC 156 provides that the term of a patent “shall be extended … from the original expiration date of the patent” if the proper conditions are met. Section 156 makes no mention of terminal disclaimers.

Holding: On appeal, the CAFC found that it is permissible — and in-fact mandatory — to tack-on Section 156 extensions to the term of a terminally disclaimed patent. 

Analysis: The statute says the term “shall be extended.” That wording implies a duty to extend once the requisite conditions are met. According to the CAFC, since a terminal disclaimer is not an explicit exception to the rule, it cannot be read-in. This reading of the statute is buttressed by the fact that terminally disclaimed patents are explicitly excluded from 154(b) term adjustments.  (expressio unius).

One thought on “Terminal Disclaimer Does Not Negate Hatch-Waxman Term Extension

  1. 1

    Seems like a no brainer – the terminal disclaimer sets the “original expiration date” and any other statute based on the expiration date would apply.

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