July 28, 2014

Edwards Lifesciences v. Corevalve – Pig Valve Implants Enabling

In Edwards Lifesciences AB v. Corevalve, Inc. (now a part of Medtronic), Appeal No. 2011-1215-1257 (Fed. Cir. Nov. 13, 2012), Corevalve challenged the validity of US Pat. No. 5,411,552 directed to a “transcather heart valve” on the basis that the valve had only been implanted in pigs as of the effective filing date of the patent, and that not all of the experimental implants were successful. The Fed. Cir. disagreed, and Edwards provides a succinct review of the standards for enablement based on animal testing.

The panel began by reminding the parties that “[t]he enablement requirement is met if the description [in the specification] enables any mode of making and using the invention.” Johns Hopkins Univ. v. CellPro, Inc. 152 F.3d 1342, 1361 (Fed. Cir. 1998). In other contexts, this statement permits claims based on “benchtop” syntheses, even if the claimed compound or process is being produced or practiced on a pilot plant scale. “The most efficient commercial embodiment need not be disclosed. Durel Corp. v. Osram Sylvania, Inc., 256 F.3d 1298 (Fed. Cir. 2001).”

However, I found almost nostalgic the panel’s statement that “it has long been recognized that when experimentation on human subjects is inappropriate, as in the testing and development of new drugs and medical devices, the enablement requirement may be met by animal tests or in vitro data. See MPEP s. 2164.02….In re Brana, 51 F.3d 1560, 1566 (Fed. Cir. 1995) (“one who has taught the public that a compound exhibits some desirable pharmaceutical property in a standard experimental animal has made a significant and useful contribution to the art, even though it may seem eventually appear that the compound is without value in the treatment of humans”).”

It does not seem that long ago to me that Examiner’s routinely rejected claims to methods of medical treatment, and even to new compounds, on the basis that they lacked utility, or “how-to use” under s. 112, if the only biodata submitted was obtained in vitro or via animal testing. This was a particular problem during the early years of the AIDS epidemic, when there were no animal models for HIV-infection (not even the SCID mouse). The Office would allow claims to new compounds based on in vitro HIV inhibition of infectivity, but restricted out and rejected method of treatment claims as non-enabled.

This policy changed some time in the 90′s – Brana was a watershed decision – although the MPEP continues to permit Examiner’s to reject data from in vitro and even in vivo model systems if the models cannot be shown to “correlate” to efficacy in humans, a term for which adequate standards have never been articulated. Ironically, some in vitro data generated using cancer cell lines  has been shown to be more predictive of in vivo activity in humans than activity against murine tumors, but don’t be hesitant to ask “your” inventor for help in this area. In Edwards, there was ample testimony that pig hearts were good, art-recognized models on which to test heart valves and delivery devices. Of course, some patients with failing valves receive valves comprising of pig tissue.

There are also still Examiners who feel that the PTO is the “gateway to the FDA” and that they are the gatekeepers. The panel in Edwards rejected this notion, citing Scott v. Finney, 34 F.3d 1058, 1063 (Fed. Cir. 1994) (“Testing for the full safety and effectiveness of a prosthetic device is more properly left to the [FDA]. Title 35 does not demand such human testing occur within the confines of [PTO] proceedings.”).

© 2014 Schwegman, Lundberg & Woessner, P.A. All Rights Reserved.

About the Author


Warren Woessner is a registered patent attorney and a founding shareholder of Schwegman, Lundberg & Woessner. His practice focuses on chemical patent law, including biotechnology, pharmaceuticals, vaccines, medical treatments, diagnostics, and biofuels and agricultural chemistry, including related opinion and licensing matters.


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