CAFC Affirms Invalidation of Replacement Heart Valve Patent – Reiterates that Reasonable Expectation of Success is not Absolute Certainty for Success

May 08, 2020 – Article

           The Federal Circuit issued a public opinion in Boston Scientific Scimed, Inc., v. Andrei Iancu, No. 2018-2004 (Fed. Cir. May 6, 2020) (sealed opinion was previously issued on April 27, 2020), affirming the PTAB’s final written decision in IPR 2017-00060. The CAFC upheld that challenged claims 1-4 of U.S. Patent No. 8,992,608 to Boston Scientific are invalid as being obvious over prior art.

Independent claim 1 of the ’608 patent recites (emphasis added):

A system for replacing a heart valve, comprising:

an expandable anchor having a collapsed delivery configuration and an expanded configuration, the expandable anchor comprising a distal end;

a replacement valve commissure support element attached to the expandable anchor;

a commissure portion of a replacement valve leaflet attached to the commissure support element; and

a fabric seal at least partially disposed around an exterior portion of the expandable anchor when the anchor is in the expanded configuration, the fabric seal having an undeployed state and a deployed state, wherein in the deployed state the fabric seal comprises flaps that extend into spaces formed by native valve leaflets;

wherein a distal end of the replacement valve leaflet is attached to the fabric seal and when the expandable anchor is in the collapsed delivery configuration, the fabric seal extends from the distal end of the replacement valve and back proximally over the expandable anchor, the fabric seal being adapted to prevent blood from flowing between the fabric seal and heart tissue.

            Notably, to address the risk of paravalvular leakage, the ’608 patent uses the fabric seal, where in the deployed state, the fabric seal comprises flaps that extend into spaces formed by the native valve leaflets, and thus the fabric seal is adapted to prevent blood from flowing between the fabric seal and the heart tissue.

            In its final written decision, the PTAB found that WIPO International Publication No. WO 03/047468 (“Spenser”) discloses a transcatheter heart valve (THV) with a fabric cuff to prevent paravalvular leakage, and U.S. Application Publication No. 2003/0236567 (“Elliot”) discloses a stent graft with a fabric skirt that forms flaps to better conform to irregular or calcified vessel walls, which when combined, would arrive at a THV with a fabric seal adapted to prevent blood from flowing between the fabric seal and heart tissue as recited in claim 1.

            Boston Scientific argued that the PTAB used impermissible hindsight analysis, and that a person of ordinary skill in the art would not have been motivated to combine the THV of Spenser with the fabric seal of Elliot.

            In its decision, the CAFC affirmed PTAB’s finding that a person of ordinary skill in the art would have been motivated to combine the teachings of Spenser and Elliot, because substantial evidence supported that the well-known problems of paravalvular leakage and endo-leakage in prosthetic and stent grafts were addressed by the prior art, and that it was obvious and known to a person of ordinary skill in the art at the time of the patent’s filing that the stent graft and prosthetic heart valve technologies were interchangeable. The court found that the evidence sufficiently supported a reasonable expectation of success in combining the THV of Spenser with the fabric skirt of Elliot to prevent paravalvular leaks in the THV.

            This decision reiterates that a finding of a reasonable expectation of success does not require “absolute certainty” for success.Pfizer, Inc. v. Apotex, Inc., 480 F.3d 1348, 1364 (Fed. Cir. 2007) (holding that expectation of success need only be reasonable, not absolute); PAR Pharm., Inc. v. TWI Pharm., Inc., 773 F.3d 1186, 1198 (Fed. Cir. 2014).