HULIQ -- The U.S. Food and Drug Administration is going to conduct some tests in order to find out if two transplant drugs have anything to do with a rare central nervous system disorder. U.S. health regulators suspect Roche’s CellCept and Novartis’ Myfortic to cause progressive multifocal leukoencephalopathy (PML). Both drugs are used to prevent rejection in organ transplantation. Its increasing application in treating lupus nephritis has demonstrated more frequent complete response and less frequent complications.