Health Canada, Canada’s health regulatory agency, has updated the label information for the multiple sclerosis drug Gilenya (fingolimod) to include stronger safety warnings on the risk of skin cancer and the rare brain infection progressive multifocal leukoencephalopathy (PML), which can be fatal.
Gilenya, a prescription drug, is used in the treatment of relapsing-remitting multiple sclerosis (MS) to reduce the frequency of attacks (relapses) and delay the progression of physical disability. Gilenya is used specifically when other MS treatments have not been effective or cannot be tolerated, Health Canada explains.
Gilenya modifies the immune system and reduces the access of certain immune cells (white blood cells known as lymphocytes) to the brain and spinal cord, which may reduce the damage that occurs in these areas in MS and the frequency of MS relapses. In a safety review, Health Canada found that Gilenya, like other drugs that suppress the immune system, may increase the risk of lymphomas and other cancers, particularly skin cancers.
Drugs that suppress the immune system also reduce the body’s ability to fight infections. PML, a rare infection caused by the John Cunningham (JC) virus, has been reported in Gilenya users—including in patients who were not currently taking and had not previously taken other immunosuppressant medications. The JC virus is a common virus and is harmless in most people but can cause PML in patients with weakened immune systems. In severe cases, it can lead to disability or death. The U.S. National Institute of Neurological Disorders and Stroke (NINDS) says PML has a mortality rate of 30-50 percent in the first few months following diagnosis but this depends on the severity of the underlying disease and treatment received. Those who survive PML can be left with severe neurological disabilities, according to NINDS.
Gilenya labeling already contained information on the possible risk of lymphoma, and warnings that the drug reduces the body’s ability to fight infection. Health Canada directed updating of label information to include the risk of skin cancer and PML specifically, and to advise patients and health care professionals to be alert for symptoms.
Skin cancer signs include changes in the size, shape or color of moles, or open sores that do not heal. Anyone taking Gilenya who experiences such signs should talk to a doctor. Basal cell carcinoma (BCC), a common skin cancer, is the type most often reported by Gilenya users. Patients who experience worsening of their MS symptoms should speak to a doctor. Such symptoms might include new or worsening weakness, trouble using the arms or legs, and changes in thinking, memory, eyesight or balance. These symptoms could indicate that the person is developing PML.
Health Canada says patients taking Gilenya should not use other medications that suppress or change how the immune system works when they are taking Gilenya because this can increase the risk of infection and PML.
If a doctor suspects PML in a patient taking Gilenya, Health Canada advises that Gilenya be suspended until PML has been ruled out.