Filewrapper®

Equivalent not tangentially related to amendment, doctrine of equivalents unavailable

March 20, 2007
Post by Blog Staff

In a case coming before the Federal Circuit for the second time, the court reversed a finding of infringement under the doctrine of equivalents because of prosecution history estoppel. The court rejected the patentee's argument that the amendment was only tangentially related to the equivalent, thus the Festo presumption of surrender of equivalents was not rebutted, and not infringement was found.

Judge Rader concurred, and offered his view that the "tangentially related" Festo rebuttal option must be construed very narrowly, even going so far as to say that the two cases where the Federal Circuit has found equivalents to be tangentially related to an amendment that "frankly, [the Federal Circuit] might well have justifiably reached a different result in both."

More details of the case after the jump.

The patentee, Cross Medical, amended claim 5 of the patent at issue to require a "seat means" with threads that extend "to a depth below the diameter of the rod" in order to screw into vertebrae. The figures below illustrate the screw, threads, rod, and bone:

After its initial product was found to infringe, the defendant, Medtronic, redesigned its screw to use a undercut that does not engage any surface on the corresponding set screw, thus making it so the screws do not extend "to a depth below the diameter of the rod." Despite this design-around, the district court held that Medtronic still infringed the patent under the doctrine of equivalents, specifically that the amendment adding the thread depth limitation was only tangentially related to Medtronic's equivalent.

The Federal Circuit disagreed. First, the court noted that the amendment was in response to a rejection under 35 U.S.C. § 112 , and that such an amendment can give rise to prosecution history estoppel. The court then turned to whether "the rationale underlying the narrowing amendment [bore] no more than a tangential relation tot he equivalent in question." As stated by the court, "an amendment made to avoid prior art that contains the equivalent in question is not tangential," but "it does not follow, however, that equivalents not within the prior art must be tangential to the amendment." Here, the thread depth limitation was added to overcome the § 112 rejection. As a result, the court analogized the amendment to one where a limitation was added to avoid prior art. Because the patent would not have issued absent the addition of the limitation, it was not tangential to the equivalent that did not include the limitation.

Judge Rader showed that he doesn't like the tangentially related Festo rebuttal method. He all but argued that maybe it doesn't even really exist separate and apart from the "unforeseeable equivalent" rebuttal method, in that he cites an intellectual property newsletter item and describes it parenthetically as "questioning whether there is, in practice, a separate tangential relation criterion or whether the three criteria established in Festo really boil down to simply an all encompassing foreseeability test." Judge Rader also points out all the "public notice" problems that the tangentially related method presents. If nothing else, we now know that Judge Rader isn't a fan of the argument that an amendment is tangentially related to an asserted equivalent.

To read the full decision in Cross Med. Prods., Inc. v. Medtronic Sofamor Danek, Inc., click here.


Post Categories

Comments (0)
Post a Comment



Captcha Image
Return to the Filewrapper Blog

Search Posts

Purpose

The attorneys of McKee, Voorhees & Sease, P.L.C. designed this blog as an informational and educational resource about intellectual property law for our clients, other attorneys, and the public as a whole. Our goal is to provide cutting-edge information about recent developments in intellectual property law, including relevant case law updates, proposed legislation, and intellectual property law in the news.

Disclaimer

McKee, Voorhees & Sease, P.L.C. provides this blog for general informational purposes only. By using this blog, you agree that the information on this blog does not constitute legal or other professional advice and no attorney-client or other relationship is created between you and McKee, Voorhees & Sease, P.L.C. Do not consider this blog to be a substitute for obtaining legal advice from a qualified, licensed attorney. While we try to revise this blog on a regular basis, it may not reflect the most current legal developments. We consciously refrain from expressing opinions on this blog and instead, offer it as a form of information and education, however if there appears an expression of opinion, realize that those views are indicative of the individual and not of the firm as a whole.

Connect with MVS

Enter your name and email address to recieve the latest news and updates from us and our attorneys.

Subscribe to: MVS Newsletter

Subscribe to: Filewrapper® Blog Updates

  I have read and agree to the terms and conditions of McKee, Voorhees & Sease, P.L.C.