Source: https://www.fdalawblog.net/2012/01/leap-year-and-hatch-waxman-an-unusual-conundrum-years-in-the-making/
Timestamp: 2019-04-26 11:43:16+00:00

Document:
It’s absolutely amazing how, after nearly 28 years, the 1984 Hatch-Waxman Amendments continue to provide surprises. Consider the latest example we came upon recently (with a little help) involving PRISTIQ (desvenlafaxine) Extended-Release Tablets.
FDA approved PRISTIQ under NDA No. 021992 in a leap year, on February 29, 2008 at 3:15 PM Eastern Time (within business hours). PRISTIQ is listed in the Orange Book with a single patent – U.S. Patent No. 6,673,838 (“the ‘838 patent”) expiring on February 11, 2022. PRISTIQ is also identified in the Orange Book as a New Chemical Entity (“NCE”) with a period of 5-year exclusivity that expires in a non-leap year, on March 1, 2013. The combination of an Orange Book patent listing and the 5-year NCE period granted to NDA No. 021992 sets up the possibility under the FDC Act that an ANDA (or a 505(b)(2) application) containing a Paragraph IV certification to the ‘838 patent could be submitted on the so-called “NCE-1 date.” But is the correct 2012 (also a leap year) submission date March 1st or February 29th?
If an application submitted under [FDC Act § 505(b)] for a drug, no active ingredient (including any ester or salt of the active ingredient) of which has been approved in any other application under [FDC Act § 505(b)], is approved after September 24, 1984, no application may be submitted under [FDC § 505(j)] which refers to the drug for which the [FDC Act § 505(b)] application was submitted before the expiration of five years from the date of the approval of the application under [FDC Act § 505(b)], except that such an application may be submitted under this subsection after the expiration of four years from the date of the approval of the [FDC Act § 505(b)] application if it contains a [Paragraph IV] certification . . . .
In the case of PRISTIQ, “four years from the date of the approval” of NDA No. 021992 is February 29, 2012, not March 1, 2012. If one were to use the often-referred-to “NCE-1 date” in this case, which calculates the submission date backwards beginning on the date of NCE exclusivity expiration, it would yield March 1, 2012, not February 29, 2012.
So what’s the lesson here? Beware of Hatch-Waxman shorthand and do the math under the statute. After all, we all know how dates count and how counting can lead to controversy (and even changes in the law) – think ANGIOMAX (for which a settlement was just announced); also, see our previous post on counting here.
UPDATE: A new note was added to the Orange Book stating: "Applications referencing NDA 021992 Pristiq (Desvenlafaxine Succinate) and challenging the listed patent may be received by the Agency beginning on Feb 29, 2012, four years from the NDA approval date."

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