The maker of the psoriasis drug Raptiva  has warned that a patient taking it developed progressive multifocal leukoencephalopathy, or PML, a fatal brain infection.  Raptiva is the second Genentech medication to be linked to PML.  Last month, the company revised a warning on Rituxan to reflect the case of a rheumatoid arthritis patient who was treated with the medicine and died from the disease. Genentech said it will work with the Food & Drug Administration (FDA) to update the prescribing information for Raptiva and determine if further action is need

PML attacks the brain and central nervous system and is usually fatal.  It is caused by a polyomavirus, called the JC virus. The JC virus is often acquired during childhood. Most adults have been infected with the JC virus but do not develop PML. The virus appears to remain inactive until something (such as a weakened immune system) allows it to be reactivated and start to multiply. People with a weakened immune system or people taking drugs that suppress their immune system (immunosuppressants like Raptiva) are most likely to get the disease. Symptoms include vision problems, loss of coordination, and memory loss. Patients who survive the disease are often permanently disabled.

According to a letter Genentech recently sent to healthcare providers, a 70-year-old Raptiva patient who took the drug for more than four years developed PML.  The company said that Raptiva may have contributed to the onset of the disease.  A second 62-year-old Raptiva patient developed progressive neurologic symptoms and died of unknown causes.

Genentech said patients who are currently on Raptiva therapy should discuss the benefits and risks of treatment with their physicians.  However, patients should not to change or stop treatment without first talking with their physician.

Raptiva is an injectable drug that was approved by the FDA in 2003 to treat moderate to severe plaque psoriasis.  Raptiva works by blocking the activation of certain immune cells called T cells, and the migration of those cells into the skin. By blocking T-cell activation and the movement of these cells into the skin, Raptiva interrupts the cycle of psoriasis.  Serious infections and malignancies reported in patients taking Rapitva include malignant melanoma and non-melanoma skin cancer, non-cutaneous solid tumors, and lymphomas.