Although the  Federal  Circuit had  previously affirmed a district court’s ruling that the asserted claims were not invalid, the Federal Circuit later vacated  the district court’s award of damages because the patent claims were found unpatentable in a later U.S. PTO re-examination decision that was affirmed by the Federal Circuit. Fresenius USA, Inc. v. Baxter  Int’l, Inc., Nos. 2012-1334, -1335 (Fed. Cir. July 2, 2013). The Federal Circuit reasoned that its first decision affirming the district court decision on validity was not a final ruling that precluded the PTO determination of invalidity because certain damages issues remained outstanding in the district court case. The patentee requested rehearing, but the Federal  Circuit denied the request. There  were  two  opinions dissenting from the denial of the request for rehearing. In one opinion, Judge O’Malley opined that the Federal Circuit’s earlier ruling of invalidity was sufficiently final that it was immune from the PTO’s later determination. The parties had fully litigated, through appeal, the issues of infringement, validity, and past damages. Thus, Judge O’Malley believed that the decisions on those issues were fixed  and could not be affected by the PTO’s later decision. According to that dissent, the PTO’s ruling eliminated only the patentee’s future rights against other parties. In the other dissenting opinion, Judge Newman warned that the Federal Circuit’s ruling infects all judicial patent rulings with uncertainty because they remain vulnerable to contrary PTO decisions until litigation is complete. According to Judge Newman, when, as here, a court is not able to undo a previous ruling, an administrative agency such as  the  PTO  should not be able to do so either. Given the differing views among the Federal Circuit judges, it is likely that the Supreme Court will be asked to address this issue.