United States: When Are Swashbuckling Experts Seemingly ‘Flooding' A Court With Large Number Of References?

Last Updated: November 17 2017
Article by Thomas A. Haag

In Bayer Pharma AG v. Watson Laboratories, Inc. (Fed. Cir. November 1, 2017), the Federal Circuit overturned the District of Delaware's finding that Watson failed to prove by clear and convincing evidence that the subject matter encompassed by the claims of Bayer's U.S. Patent 8,613,950 (the '950 patent) was obvious under 35 USC 103. The CAFC invalidated claims 9 and 11 of the '950 patent as unpatentably obvious. The Federal Circuit made this determination de novo based on the underlying findings of fact from the district court.

The '950 patent is directed to vardenafil hydrochloride trihydrate for the treatment of erectile dysfunction ("ED"), which is marketed by Bayer under the name Levitra®. Levitra is formulated as an orally disintegrating tablet ("ODT") for rapid release in the mouth. Watson filed an Abbreviated New Drug Application ("ANDA") to obtain marketing approval of a generic version of Levitra, under the name Staxyn.

The claims at issue in the '950 patent, are directed to a rapidly disintegrating oral drug formulations of vardenafil hydrochloride trihydrate comprising at least two sugars (independent claim 8) wherein the two sugars are sorbitol and mannitol (dependent claim 9) and wherein at least one sugar is mannitol (dependent claim 11).

Watson provided nine references in conjunction with Dr. Jacobs' testimony in support of its position that the claimed formulations were obvious. However, the District Court upheld the claims as valid and non-obvious because it deemed Bayer's expert Dr. Wicks' testimony more credible than Watson's Dr. Jacobs in demonstrating that the skilled artisan would not have been motivated to formulate vardenafil as an ODT. The trial court took at face value Dr. Wicks' statement that "ODTs were not considered particularly applicable to this area" and cited his pointing to the absence of any other ODT formulations of ED drugs.

In overturning this finding, the Federal Circuit stated that the district court's clear error was in its failure to address the references Watson relied upon to show a motivation to formulate ED drugs as ODTs. The Federal Circuit indicated that "these references are highly relevant to whether a person of ordinary skill in the art would have been motivated to formulate ODT vardenafil." Specifically, the Federal Circuit felt these nine references directly "contradicted" Dr. Wicks and the district court failed to consider them.

The Federal Circuit dismissed as untenable, Bayer's argument that Watson had ostensibly "flooded" the district court with irrelevant references it had failed to adequately address in its pleadings. The CAFC noted that the references at issue had been submitted to only support a very narrow point, i.e., that ODT formulation of ED drugs was known. While the Appeals Court acknowledged a district court's right to gauge witness credibility, ignoring a "wealth of evidence" not addressed by Bayer's expert constituted a reversible clear error. Moreover, the fact that the FDA had not previously approved an ODT ED drug was also irrelevant with respect to the sufficiency of motivation to create such a drug in the context of Section 103 obviousness.

Regarding the formulations containing sorbitol and mannitol recited in claim 9, the district court agreed with Dr. Wicks' testimony that an ordinarily skilled artisan would not have selected those two sugars to formulate an ED drug as claimed. Specifically, the district court found persuasive Dr. Wicks' testimony that, "every ODT on the market in the relevant prior art timeframe contained only a single sugar alcohol," and that there, "was nothing in the prior art that would have given the [person of ordinary skill in the art] a reason to use sorbitol in addition to mannitol in an ODT."

The Federal Circuit again indicated that it was the prerogative of the district court to determine witness credibility. However, it held that the lower court clearly erred in ignoring Watson's reference to SPI Pharma's Pharmaburst® prior art off the shelf ODT excipient, which contains both mannitol and sorbitol. Thus it stated, "there can be no question that it was known as of the '950 patent's priority date to use sorbitol and mannitol in ODT formulations." Therefore, the CAFC concluded that Watson's evidence "expressly demonstrated that sorbitol and mannitol in ODTs was known in the art and that there were advantageous reasons to use them."

The district court held that even if Watson had initially established proper motivation with respect to the prior art and the claims of the '950 patent; Bayer had successfully rebutted this position by showing that the prior art taught away from formulating vardenafil as an ODT. According to Bayer, the basis for the teaching away argument was the fact that vardenafil has a naturally bitter flavor on the one hand; and that oral release could result in a potentially harmful dosage spike on the other. However, the Federal Circuit citing In re Mouttet, 686 F. 3d 1322 (Fed. Cir. 2012) dismissed the lower court's holding because, "in assessing whether prior art teaches away, that 'better alternatives exist in the prior art does not mean than an inferior combination is inapt for obvious purposes." In other words, just because the prior art combination suggests that a combination is not optimal does not mean that it teaches the combination to be inoperable for obviousness purposes. The Federal Circuit clarified that "obviousness does not require that the motivation be the best option, only that it be a suitable option from which the prior art did not teach away.'"

Practice notes: When arguing for the invalidity of a patent claim, do not hesitate to raise many references in support of a very specific and narrow point of logic. On the other hand, when arguing in favor of the validity of a claim in the context of an obviousness attack, make sure that assertions that the art combination "teaches away" are substantiated by a showing that the prior art combination is inoperable and not merely a disfavored option.

The content of this article is intended to provide a general guide to the subject matter. Specialist advice should be sought about your specific circumstances.

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