By Lawrence Hurley
WASHINGTON (Reuters) - The top U.S. patent court's chief judge stepped down from his leadership role on Friday after a newspaper report said he had to recuse himself from two cases because of an email he sent praising a lawyer who appears before the court.
Judge Randall Rader will remain on the U.S. Court of Appeals for the Federal Circuit, but he will be replaced as chief judge by Judge Sharon Prost at the end of May, the court said on its website.
The court did not explain why Rader resigned before his seven-year term as chief judge, which is a mainly administrative role, was due to end in 2017.
On Thursday, The Wall Street Journal reported that Rader had recused himself from two patent cases because of concerns about impartiality. It said Rader sent an email to Edward Reines, a lawyer at law firm Weil Gotshal & Manges, praising his work. Reines had appeared before the court on behalf of software company Microsoft Corp and medical technology group Medtronic Inc respectively, in the two cases, according to the court's docket.
Rader, Reines and a court spokesman could not immediately be reached for comment.
One of the cases was a patent appeal in which DataTern Inc accused Microsoft and German rival SAP AG of patent infringement. The case was decided by a three-judge panel including Rader on April 4, partially in favor of Microsoft and SAP. Rader wrote a dissenting opinion.
On May 5, the court reissued its decision, but excluded Rader's dissent, noting he had been recused from the case.
Rader also recused himself from a patent dispute between Medtronic and rival Edwards Lifesciences Corp.
The federal circuit, which has exclusive jurisdiction over patent appeals, has become increasingly important in recent years due to high-stakes litigation over technology patents.
Rader was appointed to the court by President George H.W. Bush in 1990 and became chief judge in 2010.
(Editing by Kevin Drawbaugh and Grant McCool)