In Re Huai-Hung Kao

639 F.3d 1057, 2011 WL 1832537
CourtCourt of Appeals for the Federal Circuit
DecidedMay 13, 2011
Docket2010-1307, 2010-1308, 2010-1309
StatusPublished
Cited by75 cases

This text of 639 F.3d 1057 (In Re Huai-Hung Kao) is published on Counsel Stack Legal Research, covering Court of Appeals for the Federal Circuit primary law. Counsel Stack provides free access to over 12 million legal documents including statutes, case law, regulations, and constitutions.

Bluebook
In Re Huai-Hung Kao, 639 F.3d 1057, 2011 WL 1832537 (Fed. Cir. 2011).

Opinion

LINN, Circuit Judge.

Endo Pharmaceuticals, Inc. (“Endo”) is the assignee of three patent applications related to controlled-release tablets containing the opioid narcotic oxymorphone. The Board of Patent Appeals and Interferences (“the Board”), in separate appeals, affirmed the rejection of the claims of each application as obvious, and Endo has separately appealed each decision to this court.

The Board affirmed the rejection of all pending claims of United States Patent Application No. 11/680,432 (“the '432 Application”), United States Patent Application No. 12/167,859 (“the '859 Application”), and United States Patent Application No. 11/766,740 (“the '740 Application”) principally over a prior art international patent application that is involved in each appeal. Endo timely appealed each decision of the Board, and this court has jurisdiction under 28 U.S.C. § 1295(a)(4)(A).

Because the Board based its conclusion of obviousness regarding the '432 Application on factual findings lacking in substantial evidence, this court vacates and remands. Because the Board’s conclusions regarding the obviousness of the '859 and '740 Applications were supported by substantial evidence, this court affirms the Board’s decisions regarding those two applications.

Background

I. The '432 Application

The claimed invention of the '432 Application relates to drug formulations containing opioids, a type of narcotic frequently used to manage chronic pain. To provide consistent pain relief, a minimum level of the opioid must be maintained in the blood. Opioids, however, are typically available in immediate release formulations that quickly release the entire dose of the opioid into the body. Moreover, some opioids are rapidly metabolized by the liver (a phenomenon known as the “first-pass effect”) resulting in the drug having a low “bioavailability.” When a drug has low bioavailability this means that only a small amount of the drug is systemically available throughout the body. Because of these drawbacks, immediate release opioid formulations must be administered frequently (e.g., every 4-6 hours) to maintain continuous pain relief. But frequent administration of opioids can result in a variety of side effects, ranging from disturbed sleep to altered mental states.

To overcome the difficulties associated with immediate release formulations, the '432 Application discloses controlled release formulations containing the opioid oxymorphone, and capable of relieving pain for between twelve and twenty-four hours.

Independent claims 1 and 20, as well as dependent claims 2-3 and 5-19, are pending in the '432 Application. Because the '432 Application was filed under the Accelerated Examination Program of the United States Patent and Trademark Office (“the Office”), Endo was limited to arguing the patentability of independent claims 1 and 20. Claim 1 reads as follows (relevant terms emphasized):

1. An analgesically effective controlled release pharmaceutical composition with a twelve hour dosing interval in the form of a tablet, comprising oxymorphone or a pharmaceutically acceptable salt thereof as the sole active ingredient in the tablet and a controlled release delivery system comprising at least one pharmaceutical excipient, wherein upon placement of the composition in an in vitro *1062 dissolution test comprising USP Paddle Method at 50 rpm in 500 ml media having a pH of 1.2 to 6.8 at 87° C, about 15% to about 50%, by weight, of the oxymorphone or salt thereof is released from the tablet at about 1 hour in the test.

Claim 20 is similar to claim 1 but recites that “about 45% to about 80%, by weight, of the oxymorphone or salt thereof is released from the composition at about four hours in the test, and at least about 80%, by weight, of the oxymorphone or salt thereof is released from the composition at about 10 hours in the test.”

The examiner rejected claims 1 and 20 as obvious in view of Patent Cooperation Treaty Publication No. WO 01/08661 to Maloney (“Maloney”), both alone and in combination with United States Patent No. 5,047,248 to Calanchi et al. As is relevant here, the examiner found that, with the exception of the claimed dissolution rate, Maloney disclosed controlled release opioid formulations that taught the recited limitations. The examiner stated that the burden fell on Endo to show why Maloney failed to satisfy the claimed dissolution rate because, in her view, the controlled release system described by Maloney satisfied the other limitations of the claims.

In response, Endo submitted declarations explaining that because Maloney only disclosed a dissolution profile for a controlled release formulation containing oxycodone, an opioid with markedly different bioavailability than oxymorphone, it provided little guidance on the appropriate design of a controlled release oxymorphone formulation. The declarations further explained that controlled release oxymorphone formulations exhibit an unexpected result: Over time the formulations cause multiple peaks in oxymorphone blood concentration, which help prevent patients from building a tolerance to the opioid. Endo also included evidence that Opana® ER, a commercial embodiment of the invention, had experienced significant commercial success. The examiner concluded that the declarations were insufficient to show that Maloney did not suggest the claimed range of dissolution profiles. The examiner also found that the evidence of unexpected results and commercial success offered by Endo was not commensurate with the scope of the claims, because that evidence largely related to Opana® ER and the claims encompassed a large number of other formulations, for which no secondary considerations were shown.

On appeal, the Board affirmed the examiner’s rejection, relying exclusively on Maloney and in particular on the controlled release formulation denominated “Formula 6.” The Board recognized that Maloney disclosed that Formula 6 contains oxycodone instead of oxymorphone as recited in the claims. The Board also recognized that Maloney disclosed dissolution data for Formula 6 measured by the USP Basket Method, not the claimed USP Paddle Method. Nevertheless, the Board concluded that Formula 6 rendered the claims obvious. The Board determined that it would have been obvious to one of skill in the art to replace the oxycodone in Formula 6 with oxymorphone because Maloney generally identifies oxymorphone as a preferred opioid for use in his invention. Regarding the claimed dissolution rate, the Board found that a declaration submitted by Endo in response to the first office action suggested that the dissolution rate as measured by the Basket Method was 1.3 times faster than the rate as measured by the Paddle Method. Applying this correlation to the dissolution data for the Formula 6 oxycodone disclosed in Maloney, the Board found that Formula 6 satisfied the claimed dissolution profile. The *1063 Board then appeared to reason that if one were to substitute oxymorphone for oxycodone in Maloney’s Formula 6, the result would be an oxymorphone controlled release pill with a dissolution profile within the range of pending claim 1.

The Board then turned to the evidence of secondary considerations.

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Bluebook (online)
639 F.3d 1057, 2011 WL 1832537, Counsel Stack Legal Research, https://law.counselstack.com/opinion/in-re-huai-hung-kao-cafc-2011.