FDA issues a Communication About an Ongoing Safety Review of CellCept and Myfortic

April 10, 2008--FDA is investigating a potential association between the use of CellCept (mycophenolate mofetil) and Myfortic (mycophenolic acid), medicines used to prevent organ rejection, and the development of progressive multifocal leukoencephalopathy (PML), a life-threatening disease.

PML is a rare disorder that affects the central nervous system. When it occurs, it is usually in patients with immune systems suppressed by disease or medicines. It happens when the polyomavirus, also known as the JC virus, is activated. The JC virus is found in most adults but does not usually cause symptoms. Scientists do not know exactly how the JC virus is activated. Once activated, the JC virus attacks the cells that make myelin, the protective coating around nerve cells. Signs and symptoms of PML can include localized neurologic signs and symptoms including vision changes, loss of coordination, clumsiness, memory loss, difficulty speaking or understanding what others say, and weakness in the legs. Many patients who develop PML die. Patients who survive may have permanent disability due to irreversible nerve damage.