Method Claims Invalid for Lack of Enablement: The Federal Circuit’s Recent Decision in Wyeth and Cordis Corp. v. Abbott Laboratories


By Paul E. Dietze and Michael Shen1

In Wyeth and Cordis Corp. v. Abbott Laboratories, 2012-1223, -1224 (Fed. Cir. June 26, 2013), the Court of Appeals for the Federal Circuit affirmed the district court’s grant of summary judgment in favor of the defendants, holding method of treatment claims invalid under 35 U.S.C. § 112(a) (2012) as not being enabled for their full scope. (Slip op. at 3). The Federal Circuit found undue experimentation was required to practice the full scope of method of treatment claims that involve administering a compound selected from a broad genus of compounds when the specification only discloses a single compound within that genus that has the required properties and, thus, the synthesis and testing of each compound covered by the genus would be needed to see if a compound met the claimed function. Such experimentation, even if routine, was determined to be excessive, because “routine experimentation is ‘not without bounds.’” (Id. at 9, citing Cephalon, Inc. v. Watson Pharm. Inc., 707, F.3d 1330, 1339 (Fed. Cir. 2013)).

The claims at issue were directed to methods of treating or preventing restenosis, a re-narrowing of an artery following, for example, balloon angioplasty, in a mammal by “administering an antirestenosis effective amount of rapamycin to said mammal.”2 (Id. at 3). The district court construed the term “rapamycin” to mean “a compound containing a macrocyclic triene ring produced by Streptomyces hygroscopicus having immunosuppressive and anti-restenotic effects,” that is, a genus of compounds having such properties. (Id. at 3-4). The Federal Circuit adopted this claim construction and, as construed, characterized the scope of the claims as “broad,” because they encompassed the “use of a known compound (sirolimus) and any other compounds that meet the construction’s structural and functional requirements” of rapamycin. (Id. at 7, emphasis in original). The Federal Circuit noted, however, that the shared specifications only disclosed a single rapamycin species called sirolimus having immunosuppressive and antirestenotic properties. (Id. at 7). The specifications also disclosed how to screen for these properties, but otherwise provided no further guidance as to what other rapamycin compounds may have these properties. (Id. at 7).

The Federal Circuit identified the number of rapamycin compounds that could potentially have immunosuppressive and antirestenotic effects as numbering in the tens of thousands and that each would need to be synthesized and tested to determine if they had the desired activity. This is because the “specification is silent about how to structurally modify sirolimus, let alone in a way that would preserve the recited utility.” (Id. at 8). Without such guidance, the Federal Circuit determined that “there is no genuine dispute that it would be necessary to first synthesize and then screen each candidate compound using the assays disclosed in the specification to determine whether it has immunosuppressive and antirestenotic effects.” (Id. at 8, emphasis in original). The Federal Circuit also relied on evidence that the art was unpredictable and testimony that one does not know if a compound has the required activity unless it is tested. (Id. at 8). This synthesis and testing of at least tens of thousands of compounds was determined to be excessive and undue. (Id. at 8). Thus, the Federal Circuit concluded “there is no genuine dispute that practicing the full scope of the claims, measured at the filing date, required undue experimentation.” (Id. at 10).

The Wyeth decision demonstrates that a method claim that involves providing a compound selected from a genus of compounds so as to achieve a specified result (such as a method of treating a disorder by administering a compound selected from a genus of compounds) is likely be found invalid under 35 U.S.C. § 112(a) as not being enabled for its full scope unless the claim limits the genus of compounds to those compounds that have been shown to have the desired activity or, at the very least, limits the genus of compounds to those compounds that possess structural features that are clearly identified in the specification as being responsible for the desired activity. Likewise, Wyeth makes clear that it is insufficient disclosure if the specification simply identifies a test that can be used determine if a compound has the desired activity, especially, when the genus of compounds is broad. Thus, the Federal Circuit has strengthened § 112(a) lack of enablement defenses.

If you have any questions regarding these matters, please contact:

Paul E. Dietze, Ph.D.

C. Kyle Musgrove

1 Paul E. Dietze, Ph.D., is of counsel and Michael Shen is a partner in the Washington, D.C. office of the law firm of Haynes and Boone, LLP. Their practices emphasize pharmaceutical patent counseling, patent procurement, and patent litigation. Paul may be reached at or 202.654.4580 and Michael may be reached at or 202.654.4576.
2 Claim 1 of the 146 patent is illustrative and recited: A method of preventing restenosis in a mammal resulting from said mammal undergoing a vascular catheterization, vascular scraping, vascular surgery, or laser treatment procedure which comprises administering an antirestenosis effective amount of rapamycin to said mammal orally, parenterally intravascularly, intranasally, intrabronchially, transdermally, rectally, or via a vascular stent impregnated with rapamycin.

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