A federal judge in Newark, N.J., on Thursday dismissed a class action claiming that Schering-Plough Corp. violated antitrust law by paying generic drug makers to delay introduction of knockoffs of its potassium-deficiency drug K-Dur.

Judge Joseph Greenaway Jr. adopted the report of special master Stephen Orlofsky, who found no merit in the plaintiffs’ argument that license fees Schering paid as part of a settlement of patent litigation against the competitors were presumptively anticompetitive.