Patent Obviousness – Legal Standard
Under the U.S. Patent Act, an invention cannot be patented if “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 to which said subject matter pertains.” 35 U.S.C. § 103(a). Patents are presumed to be valid. Kao Corp. v. Unilever U.S., Inc., 441 F.3d 963, 968 (Fed. Cir. 2006). A party seeking to invalidate a patent based on obviousness must demonstrate “by clear and convincing evidence that a skilled artisan would have been motivated to combine the teachings of the prior art references to achieve the claimed invention, and that the skilled artisan would have had a reasonable expectation of success in doing so.” Pfizer, Inc. v. Apotex, Inc., 480 F.3d 1348, 1361 (Fed. Cir. 2007). Clear and convincing evidence places in the fact finder “an abiding conviction that the truth of [the] factual contentions are highly probable.” Colorado v. New Mexico, 467 U.S. 310, 316 (1984) (quotation marks omitted).
The obviousness determination turns on underlying factual inquiries involving: (1) the scope and content of prior art, (2) differences between claims and prior art, (3) the level of ordinary skill in pertinent art, and (4) secondary considerations such as commercial success and satisfaction of a long-felt need. Graham v. John Deere Co., 383 U.S. 1, 17 (1966). The Supreme Court has explained that the Federal Circuit’s “teaching, suggestion or motivation” test provides helpful insight into the obviousness question as long as it is not applied rigidly. KSR Int’l Co. v. Teleflex Inc., 550 U.S. 398, 127 S. Ct. 1727, 1741 (2007). Accordingly, under KSR, “it remains necessary to identify some reason that would have led a chemist to modify a known compound in a particular manner to establish prima facie obviousness of a new claimed compound.” Takeda Chem. Indus., Ltd. v. Alphapharm Pty., Ltd., 492 F.3d 1350, 1357 (Fed. Cir. 2007).
If a patent challenger makes a prima facie showing of obviousness, the owner may rebut based on “unexpected results” by demonstrating “that the claimed invention exhibits some superior property or advantage that a person of ordinary skill in the relevant art would have found surprising or unexpected.” In re Soni, 54 F.3d 746, 750 (Fed. Cir. 1995). We consider the relevant factors in turn.
Identification of a Lead Compound
An obviousness argument based on structural similarity between claimed and prior art compounds “clearly depends on a preliminary finding that one of ordinary skill in the art would have selected [the prior art compound] as a lead compound.” Takeda, 492 F.3d at 1359; see also Eisai Co. Ltd. v. Dr. Reddy’s Labs., Ltd., 533 F.3d 1353, 1359 (Fed. Cir. 2008) (stating that “post-KSR, a prima facie case of obviousness for a chemical compound still, in general, begins with the reasoned identification of a lead compound” in the prior art). Teva argues that the ‘406 patent identifies 2-pyr EHDP as the most promising molecule for the inhibition of bone resorption. The trial court disagreed and concluded from the evidence that a person of ordinary skill in the art would not have identified 2-pyr EHDP as a lead compound for the treatment of osteoporosis.
We need not reach this question because we conclude that even if 2-pyr EHDP was a lead compound, the evidence does not establish that it would have been obvious to a person of ordinary skill at the time of the invention to modify 2-pyr EHDP to create risedronate.
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