District Court Case of Note: King Pharmaceuticals, Inc. v. Teva Pharmaceuticals USA Inc

TERMINALLY DISCLAIMED PATENTS ARE ELIGIBLE FOR EXTENSION UNDER 35 U.S.C. §156

In King Pharmaceuticals, Inc. v. Teva Pharmaceuticals USA Inc. 78 U.S.P.Q.2d 1237 (D. NJ. Jan. 20, 2006), plaintiff King and involuntary plaintiff Wyeth brought an action for patent infringement against defendant Teva pharmaceuticals.  King alleged that Teva infringed one or more claims of U.S. Pat. No. 4,626,538, owned by Wyeth and for which King has an exclusive license.  The ‘538 patent relates to zaleplon drug products.  The ‘538 patent was issued on Dec. 2, 1986, and is subject to a terminal disclaimer.  The ‘538 patent was initially rejected on the ground that it claimed the same invention that was claimed in an earlier application, U.S. Pat. No. 4,521,422, and the PTO granted the ‘538 patent only after the applicant filed a terminal disclaimer under 35 U.S.C. §253. 

The terminal disclaimer disclaimed any term of the ‘538 patent that would otherwise have extended beyond the ‘422 patent, which expired on June 23, 2003.  The original termination date of the ‘422 patent was June 3, 2002 (17 years from its issue date) but, pursuant to 35 U.S.C. §154, this date was reset to June 23, 2003 (20 years from its filing date).  The USPTO agreed that the ‘538 patent’s expiration date should be reset at June 23, 2003 as well since the term of the ‘538 patent was linked to the term of the ‘422 patent.  Thus, based on the terminal disclaimer, the ‘538 patent had been scheduled to expire on June 23, 2003. 

On June 4, 2003, pursuant to 35 U.S.C. §156, the PTO extended the term of the ‘538 patent for a period of 1810 days, running from June 23, 2003, based on FDA review.  Teva submitted an ANDA to the FDA seeking approval to engage in the commercial manufacture, use, and sale of zaleplon, a generic product which is bioequivalent to King’s Sonata drug products.  The crux of Teva’s argument is that the term of a terminally disclaimed patent may not be extended under 35 U.S.C. §156 and, therefore, the ‘538 patent expired on June 23, 2003. 

On the issue of whether a terminally disclaimed patent is extended under 35 U.S.C. §156, the District Court held that a terminally disclaimed patent is eligible for extension under 35 U.S.C. §156.  Specifically, the District Court held that 35 U.S.C. §156 is plain and unambiguous: a terminally disclaimed patent is not barred from receiving a 35 U.S.C. §156 extension.  The only limitations on the provision of a 35 U.S.C. §156 patent term extension are those expressly enumerated at §156(a)(1)-(5).  Nonexistence of a terminal disclaimer is not among those enumerated conditions, and, therefore, cannot be construed to be a condition for obtaining a §156 patent term extension. 

Additionally, the District Court compared 35 U.S.C.§156 and 35 U.S.C.§154(b) to show that unlike 35 U.S.C.§156, 35 U.S.C.§154(b) expressly refers to terminally disclaimed patents.  Specifically, 35 U.S.C.§154(b) provides that “[n]o patent the term of which has been disclaimed beyond a specified date may be adjusted under this section beyond the expiration date specified in the disclaimer.”  As such, 35 U.S.C. §154 demonstrates that Congress knows how to draft a clear exception barring a terminally disclaimed patent from receiving a patent term extension. 

Moreover, the District Court found that Congress amended both 35 U.S.C.§156 and 35 U.S.C. §154 in Pub. L. No. 103-465, §532 (1994), in which Congress initially enacted 35 U.S.C. §154’s exception for terminally disclaimed patents, and has amended both provisions several times since it enacted Pub. L. No. 103-465, §532 (1994).  The Court thus presumed that Congress acted intentionally and purposely when it included an exception for terminally disclaimed patents in 35 U.S.C. §154 and omitted any exception for terminally disclaimed patents in 35 U.S.C. §156. 

Lastly, the District Court noted that the United States Patent and Trademark Office, in 37 C.F.R. §1.775(a), states that “[i]f a determination is made pursuant to §1.750 that a patent for a human drug, antibiotic drug or human biological product is eligible for extension, the term shall be extended by the time as calculated in days in the manner indicated by this section.  The patent term extension will run from the original expiration date of the patent or any earlier date set by terminal disclaimer (§1.321).”  Since the PTO promulgated §1.775(a), Congress amended §156 six times.  However, Congress has never amended §156 to undermine the PTO’s interpretation of §156 or to change §156’s language to bar terminally disclaimed patents from receiving a §156 extension. 

 

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