(February 3, 2016, 1:32 PM EST) -- WASHINGTON, D.C. — A New York federal judge properly invalidated four patents covering the pain-relieving drug OxyContin following a three-week bench trial in 2013, the Federal Circuit U.S. Court of Appeals affirmed Feb. 1 (Purdue Pharma LP v. Epic Pharma LLC, et al., No. 14-1294, Fed. Cir.)....