By Donald Zuhn --
Last month, in In re Mousa, the Federal Circuit affirmed a decision by Board of Patent Appeals and Interferences sustaining the invalidity of U.S. Application No. 10/667,216 for anticipation and obviousness. The '216 application is directed to chemically fractured and modified heparin. Heparin, an anticoagulant typically used to prevent blood clots from forming, can also be used to prevent new blood vessel growth (i.e., angiogenesis) in tumors by blocking the action of fibroblast growth factor 2 (FGF2). This latter use is limited because heparin's anticoagulant properties can cause bleeding complications. Heparin can be chemically fractured into fragments called heparin fractions, which retain the anticoagulant and angiogenesis properties of heparin.
The '216 application is directed to super-sulfated, oxidized heparin fractions, which are produced by oxidizing some of the hydroxyl groups on the heparin fraction and by substituting sulfate groups for the hydrogen atoms in other hydroxyl groups. The '216 application discloses that increased oxidation of the heparin fractions fully inhibits FGF2-induced angiogenesis, and further, that the bleeding complications normally associated with heparin use can be eliminated by using these super-sulfated, oxidized heparin fractions because they possess weaker anticoagulant properties than heparin.
During prosecution, several claims of the '216 application were rejected as anticipated by, and obvious in view of, U.S. Patent No. 4,727,063 ("Naggi"), which discloses the treatment of heparin with a mixture of sulfuric acid and chlorosulfonic acid (i.e., strong oxidizing agents) to produce a super-sulfated heparin fraction having weak anticoagulant properties. Because Naggi discloses the treatment of heparin with strong oxidizing agents, the Examiner found that the Naggi heparin fractions were inherently oxidized. The Examiner also found that because the Naggi heparin fractions possessed weak anticoagulant activity, the Naggi heparin fractions inherently possessed the anti-angiogenesis properties of the heparin fractions disclosed in the '216 application.
Mousa appealed the Examiner's rejection to the Board, arguing that Naggi's method would not produce super-sulfated, oxidized heparin fractions with a chemical structure that is the same as the heparin fractions of the '216 application because Naggi did not disclose O-sulfating a first oxidized heparin fraction as in the '216 application. Mousa also argued that Naggi did not disclose a heparin fraction that fully inhibits FGF2-induced angiogenesis (a claim limitation that Mousa added during prosecution). The Board affirmed the Examiner's rejection, finding that Naggi discloses, inherently or expressly, each and every limitation of the '216 claims. In particular, the Board found that Naggi discloses super-sulfated, oxidized heparin fractions (because Naggi treats heparin with sulfuric and chlorosulfonic acids), and a weak anticoagulant property as compared to heparin. The Board concluded that the Examiner had established that the heparin fractions disclosed by Naggi and the '216 application were the same or substantially the same, and that the Examiner had properly shifted the burden of proof to Mousa to show that the Naggi heparin fractions did not inherently possess the anti-angiogenesis properties recited in the '216 claims.
On appeal, Mousa argued that Naggi does not disclose an oxidized heparin fraction or a heparin fraction that fully inhibits FGF2-induced angiogenesis. The U.S. Patent and Trademark Office countered that the Examiner established that treating heparin with the strong oxidizing agents (as disclosed by Naggi) necessarily results in oxidized heparin and that the Examiner properly shifted the burden of proof to Mousa to show that those oxidizing agents did not oxidize heparin, as well as to show that the Naggi heparin fractions did not possess the same FGF2-inhibiting characteristics as the heparin fractions of the '216 application. In affirming the Board's decision, the Federal Circuit determined that the Board's findings that the Naggi heparin fractions were inherently oxidized and possessed weak anticoagulant properties constituted substantial evidence in support of the Board's determination that Naggi discloses a super-sulfated, oxidized heparin fraction identical to the heparin fraction of the '216 application. The Court noted that:
Having established that the two heparin fractions are "the same or substantially the same compound" and that the Naggi fractions necessarily possessed the FGF2-inhibiting characteristic recited in claim 1, the Examiner properly shifted the burden of proof to Mousa to prove that the structures were different and that the claimed properties were not inherent. . . . Mousa failed to satisfy this burden. Although Mousa argues that oxidizing agents do not oxidize every substance and that the Examiner did not establish that these chemicals can oxidize heparin, Mousa provided no proof in support of this contention to the Examiner or to the BPAI.
The Court also noted that "once the Examiner established that the Naggi patent read identically on the limitations of the '216 claims, Mousa bore the burden to show that the Naggi heparin fractions did not inherently possess the FGF2-inhibiting characteristics of the '216 heparin fractions as recited by claim 1," adding that "Mousa again failed to satisfy his burden of proof." Finding that the Board's factual findings were supported by substantial evidence, the Court affirmed the Board's decision sustaining invalidity.
In re Mousa (Fed. Cir. 2012)
Panel: Circuit Judges Prost, Schall, and Reyna
Opinion by Circuit Judge Reyna