Cooper v. Goldfarb

• Decision Date: 01 September 1998
• Docket Number: No. 97-1302,97-1302
• Citation: 47 USPQ2d 1896,154 F.3d 1321
• Parties: Peter B. COOPER, Appellant, v. David GOLDFARB, Appellee.
• Court: U.S. Court of Appeals — Federal Circuit

Page 1321

154 F.3d 1321

47 U.S.P.Q.2d 1896

Peter B. COOPER, Appellant, v. David GOLDFARB, Appellee.

No. 97-1302.

United States Court of Appeals, Federal Circuit.

Sept. 1, 1998.

Donald R. Dunner, Finnegan, Henderson, Farabow, Garrett & Dunner, L.L.P., argued for appellant. With him on the brief were Albert J. Santorelli, Barbara C. McCurdy, and Howard A. Kwon.

D. Dennis Allegretti, Burns & Levinson, Boston, Massachusetts, argued for appellee. With him on the brief were Lawrence M. Green and Matthew B. Lowrie, Wolf, Greenfield & Sacks, P.C., Boston, Massachusetts. Of counsel on the brief was Francis Paintin, Woodcock, Washburn, Kurtz, Mackiewicz & Norris, Philadelphia, Pennsylvania.

Before CLEVENGER, Circuit Judge, SKELTON, Senior Circuit Judge, and SCHALL, Circuit Judge.

SCHALL, Circuit Judge.

Peter B. Cooper appeals from the decision of the United States Patent and Trademark Office (PTO) Board of Patent Appeals and Interferences (the Board) awarding priority of invention to Dr. David Goldfarb for expanded polytetraflouroethylene (PTFE) artificial vascular grafts. See Goldfarb v. Cooper, Patent Interference No. 101,100 (Bd. Pat.App. & Int. Oct. 18, 1995) (Final Decision); Goldfarb v. Cooper, Patent Interference No. 101,100 (Bd. Pat.App. & Int. Dec. 19, 1996) (Reconsideration Decision). We affirm the Board's determination that Goldfarb was the first to reduce the invention to practice. However, we reverse the Board's determination that Cooper failed to properly raise the issue of inurement, and we remand to allow the Board to consider whether Goldfarb's efforts inure to the benefit of Cooper.

BACKGROUND

A. The Technology

The invention at issue in this interference relates to an artificial vascular graft constructed from expanded PTFE tubing. Expanded PTFE is a flexible membrane constructed by stretching heated PTFE. W.L.

                Gore & Associates (Gore) sells expanded PTFE under the brand name "Gore-Tex."   In the early 1970s, expanded PTFE was manufactured by:  (1) forming a batch of paste from a PTFE resin and a lubricant;  (2) separating a portion of the batch and shaping it into a cylinder;  (3) extruding the cylinder into a short tube ("the extrudate");  (4) heating and drying the extrudate;  (5) stretching the heated extrudate by pulling the ends apart by hand, resulting in a tube approximately ten times its original length;  (6) heating the stretched tube above its melting temperature to sinter, or lock, the material, thereby making it stronger when it cooled;  and (7) cooling the tube on a rack.  The stretching process produces a PTFE structure consisting of solid nodes of PTFE connected by thin PTFE fibrils.  The distance between the nodes is referred to as "fibril length" or "inter-nodal distance."   It is this factor which in large part determines the suitability of the product for use as a vascular graft.  The primary dispute presented by the interference concerns which of the parties was the first to recognize the importance of fibril length and which was the first to reduce the invention to practice by performing a successful experiment using the claimed structure
                

B. Cooper's Research Activities

Research into the use of expanded PTFE as a vascular graft began in 1972, when Gore, in conjunction with several surgeons, conducted a series of experiments to determine the suitability of expanded PTFE as a vascular graft. In November of 1972, Cooper, the Plant Manager of Gore's facility in Flagstaff, Arizona, sent three types of expanded PTFE tubing to a number of surgeons for evaluation. Among the surgeons receiving the samples were Dr. William Sharp, of the Akron City Hospital, in Akron, Ohio, and Dr. Glenn Kelly, of the University of Colorado Medical School, in Denver, Colorado. Referred to as the "three-structure experiment," this initial research involved experiments with small, medium, and large "pore size" grafts. ¹ In the early stages of the research, the participants believed that "pore size" was the key parameter determining success as a vascular graft. During the course of the research, however, it became clear that fibril length was the critical factor. In order to function successfully, the fibrils connecting the PTFE nodes must be of sufficient length to permit infiltration by fibroblasts and red blood cells, thereby leading to tissue ingrowth into the walls of the graft. ² However, the fibrils must not be so long as to allow excessive bleeding through the walls of the graft.

In order to evaluate the performance of an artificial vascular graft, a surgeon ordinarily implants the tube-shaped sample in a blood vessel of a dog, and then harvests and examines the graft several weeks later. In 1972-73, the accepted test for viability of a graft material was whether a graft implanted in a dog remained "patent" for 21 days. The term "patent" means that a graft is clear, unobstructed, and permits blood to flow through the length of the graft. The parties agree that a single successful graft in a dog would constitute an actual reduction to practice.

In the spring of 1973, the researchers participating in the three-structure experiment began obtaining results. In a letter dated April 2, 1973, Dr. Sharp informed Cooper that two of his grafts had been successful. The letter stated:

RESULTS: Group I--416-10312-3 (.31g/cc). There were a total of four grafts inserted into the dog's carotid artery. Two remained patent in the same animal for 21 days and 2 clotted before 21 days in another animal. The low power microscopic views demonstrate excellent fibroblastic On April 17, 1973, Dr. Kelly sent Cooper four histological slides of harvested grafts. Cooper testified that he reviewed the slides under a microscope on April 22, 1973, and then photographed the slides, measured the fibril lengths shown, and recorded his conclusions in his laboratory notebook. The first page of Cooper's notebook contains a photomicrograph of a harvested graft along with a notation indicating that the graft was submitted by Dr. Kelly. The page also contains a sticker with a 100 micron scale indicated. The following is written above the photomicrograph:

infiltration of the wall of the graft (Figure # 1) and a fairly thick, but well attached neointima (Figure # 2). There was only moderate reaction externally. (Figure # 3).

I want to maximize the amount and rate of tissue ingrowth into Gore-Tex vascular prosthetics. Two qualities are necessary. 1. Uniform "poker chip" structure and 2. a minimal "skin" at both the O.D. and I.D. surfaces.

Tissue has invaded Gore-Tex where the nodes are approx. 10-30 microns thick and with most separations between nodes at about 50-100 microns. Photo # 1. Other structures having approximately 5-10 micron node dimensions and spaces from about 5-30 micron do not appear to allow ingrowth--Photo # 2.

The page is signed "Peter B. Cooper/May 1, 1973" and "Read & Understood By" "John Giovale/June 5, 1973." John Giovale, a Gore manufacturing engineer, confirmed that Cooper had shown him the photographs and discussed with him the need for sufficient internodal separation in order to allow tissue ingrowth.

The next page of Cooper's laboratory notebook is dated May 2, 1973. It refers to Dr. Kelly's experiments and samples submitted by Dr. Kelly. The page bears the following notation: "Both [samples] from Dr. Glenn Kelly U of Colorado. Femoral Vein in Dogs--Both Failed." The page was signed by Cooper on May 2 and was read and understood by Giovale on June 5.

Cooper filed Patent Application No. 05/457,711 on April 2, 1974, claiming the use of expanded PTFE as a vascular graft. ³ Cooper claimed conception as of May 1, 1973, based on the statements in his lab notebook as corroborated by Giovale. He also claimed a reduction to practice by May 1, 1973, based on Dr. Kelly's experiments, or in the alternative, based on Dr. Sharp's experiments.

C. Goldfarb's Research Activities

In January of 1973, Goldfarb moved to Phoenix, Arizona, to assume the position of Director of Research and Clinical Staff Surgeon at the Arizona Heart Institute (AHI). At that time, Goldfarb had been studying artificial vascular grafts, including PTFE, for ten years. Shortly after assuming his new position, Goldfarb was contacted by Richard Mendenhall, a Gore employee responsible for marketing PTFE. Mendenhall wanted to discuss whether AHI would be willing to test expanded PTFE vascular grafts. On February 2, 1973, Mendenhall sent a letter to Goldfarb and enclosed several articles about Gore-Tex and samples of the material.

Following a meeting with Cooper and Mendenhall in early February, Goldfarb set up an animal research facility at AHI. Over the next several months, Cooper periodically sent Goldfarb a variety of expanded PTFE tubes to use in his research. Using the samples provided by Cooper, Goldfarb conducted a series of experiments consisting of 21 grafts implanted in the left and right carotid and left and right femoral arteries of seven dogs. These experiments were corroborated by Goldfarb's assistant, Jimmy Lee Moore. Goldfarb began obtaining results from these experiments towards the end of May of 1973. On May 23, 1973, the "2-73 RC" graft was harvested, and on June 13, 1973, the "2-73 RF" graft was harvested. ⁴ Histological slides made from these specimens revealed that the grafts were patent Goldfarb testified that in May or June of 1973, he disclosed to Mendenhall and Harold Green, a Gore chemical engineer, that a successful expanded PTFE graft should have a fibril length of 5 to 100 microns. Mendenhall confirmed that Goldfarb had discussed pore sizes with him in the range of 5 to 112 microns in the spring of 1973. For his part, Green confirmed that, in June or July of 1973, Goldfarb had requested a graft having a fibril length of 5 to 112 microns. ⁵

and therefore successful. Goldfarb testified that he examined each graft, both before and after implantation, using a microscope with a calibrated eyepiece to measure...