Addressing the issue of whether disclosure of a single species and methods for identifying other species enabled method of treatment claims covering a genus of compounds, the U.S. Court of Appeals for the Federal Circuit affirmed summary judgment of invalidity for non-enablement, finding that there was no genuine dispute that practicing the full scope of the claims, measured at the time of filing, would require excessive experimentation.  Wyeth and Cordis Corp. v. Abbott Labs., Inc., Case Nos. 12-1223, -1224 (Fed. Cir., June 26, 2013) (Moore, J.). 

The patents-in-suit claim methods for treating or preventing restenosis (the re-narrowing of an artery, e.g., after balloon angioplasty) by administering an effective amount of rapamycin.  The district court construed rapamycin to include the genus of compounds containing a macrocyclic triene ring structure produced by Streptomyces hygroscopicus and having immunosuppressive and anti-restenotic effects.  The specification disclosed sirolimus, a species falling within the genus, and known assays for determining the immunosuppressive and anti-restenotic effects of candidate compounds.  The specification did not provide guidance on preferred substituent groups or on how to structurally modify sirolimus to yield compounds with anti-restenotic effects.  Based on the scope of the claimed subject matter, the district court concluded that the claimed subject matter was not enabled by the specification.  Wyeth appealed. 

The Federal Circuit agreed with the district court that the scope of the claims was broad and the art was an unpredictable one.  To identify the candidate compounds falling within the claims, one of ordinary skill in the art would need to screen each of thousands of candidate compounds in restenosis assays.  Noting that undue experimentation is a matter of degree, the Court held that the amount of experimentation in this instance was excessive.  The claimed genus potentially included tens of thousands of compounds, and the specification was silent regarding the structural modifications that would preserve the claimed utility.

The Federal Circuit found that there was no genuine dispute that it would be necessary to synthesize and then screen each candidate compound using the assays disclosed in the specification to determine whether the compound had immunosuppressive and anti-restentoic effects.   Even where the experimentation is routine, the amount of experimentation is “not without bounds.”  Here, the bounds were exceeded because the specification disclosed “only a starting point for further iterative research in an unpredictable and poorly understood field.”