By Dennis Crouch
Wyeth v. Abbot Labs (Fed. Cir. 2013)
In a unanimous opinion, the Federal Circuit has affirmed a summary judgment holding that Wyeth's patents are invalid as lacking enablement under 35 U.S.C. 112. Wyeth's patents cover the use of rapamycin antibiotic to treat and prevent restenosis following arterial balloon catheterization. See U.S. Patent Nos. 5,516,781 and 5,563,146. The claimed invention is simple and basically says, administer an "antirestenosis effective amount of rapamycin." Claim 1 of the '781 patent reads as follows:
1. A method of treating restenosis in a mammal resulting from said mammal undergoing a percutaneous transluminal coronary angioplasty 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.
One requirement of patent law is that the patent application (at the time of its filing) must sufficiently enable a person skilled in the relevant art to make and use the full scope of the claimed invention without undue experimentation. This "enablement requirement" is codified in Section 112(a) of the Patent Act (Formerly known as Section 112¶1).
Here, it is the "full scope" requirement that kills the patent. In particular, Wyeth requested and received a broad construction of the claim term rapamycin to in a way that includes a large number of molecules that are structurally analogous to one another. However, the specification only discloses a single species along with a number of assays that could be useful to ascertain whether potential compounds exhibit the requisite effect.
In the appeal, the Federal Circuit aligned itself to the rule that broad claim scope requires broad disclosure. Here, the court noted that the rapamycin definition includes "tens of thousands" of candidate molecules and the specification "is silent about how to structurally modify sirolimus.
Undue experimentation: For its part, Wyeth argued that a lab tech with the usual skill and little creativity could systematically work through the various potential candidates to find which ones actually work. Citing to Johns Hopkins Univ. v. CellPro, Inc., 152 F.3d 1342, 1360–61 (Fed. Cir. 1998), Wyeth argued that a large pile of merely routine experimentation does rise to the level of impermissible undue experimentation.
The Federal Circuit disagreed – finding that the trial-and-error process of tens-of-thousands of candidates moves the project well into the range of undue experimentation.
[T]here 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. There is no evidence in the record that any particular substitutions outside of the macrocyclic ring are preferable. Indeed, a Wyeth scientist confirmed the unpredictability of the art and the ensuing need to assay each candidate by testifying that, "until you test [compounds], you really can't tell whether they work or not [i.e., have antirestenotic effects]." J.A. 6929. In sum, there is no genuine dispute that practicing the full scope of the claims would require synthesizing and screening each of at least tens of thousands of compounds. . . .
Even putting the challenges of synthesis aside, one of ordinary skill would need to assay each of at least tens of thousands of candidates. Wyeth's expert conceded that it would take technicians weeks to complete each of these assays. The specification offers no guidance or predictions about particular substitutions that might preserve the immunosuppressive and antirestenotic effects observed in sirolimus. The resulting need to engage in a systematic screening process for each of the many rapamycin candidate compounds is excessive experimentation. We thus hold that there is no genuine dispute that practicing the full scope of the claims, measured at the filing date, required undue experimentation.
The take-away legal points here are (1) broad claims must do more to satisfy the enablement requirement than narrow claims; and (2) when excessive, routine non-creative efforts to recreate the invention can constitute undue experimentation.
The case is also interesting because it comes at a time where policymakers are looking to tighten the requirements of Section 112. As it did during the debate over the AIA, the Federal Circuit appears poised to make its mark on the current debate over patent scope and clarity.