In the district court, Watson Laboratories (“Watson”) failed to prove by clear and convincing evidence that claims 9 and 11 of U.S. Patent No. 8,613,950 (“the ‘950 patent”), assigned to Bayer Pharma AG (“Bayer”), were obvious. The ‘950 patent involves vardenafil, an erectile dysfunction drug (“ED”), in the form of an oral disintegrating tablet (“ODT”). Watson filed an Abbreviated New Drug Application to market a generic version of Bayer’s Staxyn which embodies the ‘950 patent. Bayer asserted infringement of the ‘950 patent. In response, Watson challenged the validity of claims 9 and 11 based on obviousness.
An invention is obvious when “the differences between the subject matter sought to be patented and the prior art are such that the subject matter as a whole would have been obvious at the time the invention was made to a person having ordinary skill in the art (“PHOSITA”) to which subject matter pertains.” 35 U.S.C. § 103. Determining obviousness requires an evaluation of the following factual determinations: “(1) the scope and content of the prior art; (2) the differences between the prior art and the claims at issue; (3) the level of ordinary skill in the art at the time the invention was made; and (4) objective evidence of obviousness.” Graham v. John Deere Co., 383 U.S. 1, 17–18 (1966).
Claim 8 recites the vardenafil ODT limitation. More specifically, claim 8 recites, “[a] drug formulation of an uncoated tablet which disintegrates rapidly in the mouth and releases the drug in the mouth without swallowing the tablet comprising vardenafil hydrochloride trihydrate, and at least two sugar alcohols.”
In determining whether there would have been motivation to combine the prior art—formulating vardenafil ODT—the district court improperly gave weight to the testimony of Bayer’s expert, Dr. Wicks. While Dr. Wicks’ testified that two of Watson’s prior art references did not motivate the combination of ED drugs with an ODT, he expressly conceded that other prior art described ED drugs as candidates for ODT formulations. The court clearly erred by giving unnecessary importance to the nonexistence of an ODT ED with FDA approval prior to the ‘950 patent’s priority date. Additionally, the court clearly erred by not considering six of the nine prior art references presented by Watson which disclosed the applicability of an ODT formulation with an ED. Consequently, a PHOSITA would have been motivated to combine an ODT formulation with vardenafil.
Both claims 9 and 11 depend from claim 8. Claim 9 recites the sugar alcohols as “sorbitol and mannitol” and claim 11 recites, “wherein at least one sugar alcohol is sorbitol.” The court clearly erred in finding a PHOSITA would lack the motivation to combine an ODT with sorbitol and mannitol, or at least two sugar alcohols, one of which is sorbitol, because it failed to consider numerous prior art references disclosing the addition of sorbitol to mannitol in an ODT. The court gave too much weight to the fact that every ODT on the market at the time of the ‘950 patent’s priority date contained only a single sugar alcohol, mannitol. Also, the court improperly gave credence to evidence that a PHOSITA would look at the ODT market to determine whether the FDA considered the product safe and effective.
Despite concerns in the prior art of the bitter taste and increased bioavailability, the prior art did not teach away from the immediate release limitation of vardenafil ODT. “A reference teaches away when it suggests that the line of development flowing from the reference’s disclosure is unlikely to be productive of the result sought by the applicant.” Medichem, S.A. v. Rolabo, S.L., 437 F.3d 1157, 1165 (Fed Cir. 20006). As here, between the delayed-release limitation and the immediate-release limitation, a prior art reference merely favoring one limitation over another does not render the delayed-release limitation unworkable such that it is taught away. The court did not clearly err in its fact finding regarding the delayed-release limitation and the immediate-release limitation, but it clearly erred in concluding that those findings taught away from the claimed limitation.
Weighing all of the Graham factors, a PHOSITA would have been motivated to combine the limitations as recited in claims 9 and 11. Consequently, the Court reversed the lower court’s holding.
In an obviousness inquiry, material prior art references disclosing combinations of claimed limitations cannot be disregarded based on a drug product’s commercial viability or FDA approval. Teaching away from a claimed feature requires a reference to disclose that the feature is unworkable rather than less favorable.
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