PML and MS Therapy Aug 3, 2008
PML occurs as a result of viral infection of the brain with either JC virus or BK virus. Most people actually carry these viruses in a dormant state since they have already been infected with them at an early age. (Suite101.com)
2 patients in Tysabri study found to have JC virus Mar 5, 2008
Citing a summary of a presentation set for April at the American Academy of Neurology, Corey Davis, an analyst at Natixis Bleichroeder, said an examination of 175 patients treated at one center found two cases of JC virus - one in the cerebrospinal fluid and one in the plasma. But he noted neither showed any signs of progression to progressive multifocal leukoencephalopathy, the potentially deadly brain infection. (Boston Globe)
New Therapeutic Target For Treatment Of Multiple Sclerosis Jan 25, 2008
However, they also impede the immune system's ability to provide protection against chronic viral infections of the central nervous system, such as progressive multifocal leukoencephalopathy, a demyelinating disease of the central nervous system caused by the JC virus. Since ALCAM/CD166 blockade does not affect CD8+ T cell migration, whose main function is to destroy cells infected by viruses and neoplastic cells, the study results suggest that CNS immune protection against viruses would not be... (Science Daily)
New Virus May Be Responisble For Unexplained Respiratory Infection May 19, 2007
For example, one of the most infamous polyoma viruses, the JC virus, is a leading secondary infection in HIV patients. It causes a life-threatening neurological disorder called progressive multifocal leukoencephalopathy. (Science Daily)
Scientists Reveal Virus' Secret Weapon: Sheds Light On How Brain, Kidney Viruses Infect Jan 30, 2007
While SV40 doesn't normally infect humans (it has been found in humans and was likely introduced in the 1950s via a contaminated polio vaccine), its compatriots, the polyomaviruses known as JC virus and BK virus do, and sometimes fatally. These new findings may lead to new strategies for treating or preventing infection by polyomavirus. (Science Daily)
FDA clears restricted return of MS drug Jun 7, 2006
Researchers have estimated that as many as one in every 1,000 Tysabri users might fall prey to the JC virus that causes PML. MS patients supported the return of Tysabri (pronounced ty-SAH-bree), despite its risks. "The benefits, No. 1, are worth it. No. 2, I am not afraid of dying, I am afraid of living with the disease and being a burden to my family," said Barbara Crooks, 48. (Herald Online, SC -- Health)
Previously banned MS drug to return to market Jun 6, 2006
Researchers have estimated as many as one in every 1,000 Tysabri users might fall prey to the JC virus that causes PML.. We expect, yes, that there will be other cases and, yes, there will be additional deaths. (MSNBC -- Health)
FDA Allows MS Drug Tysabri Back on Market Jun 6, 2006
The FDA has estimated that patients on Tysabri have about a one in 1,000 risk of contracting PML. The disorder is caused by the JC virus that is dormant in most humans. But the virus can be reactivated in patients with weakened immune systems from disease or from drugs that suppress the immune system. (SmartMoney)
MS Drug Pulled For Dangers To Make Comeback Jun 6, 2006
Researchers have estimated that as many as one in every 1,000 Tysabri users might fall prey to the JC virus that causes PML. MS patients supported the return of Tysabri, despite its risks. Ireland-based Elan distributes the drug. (Click2Houston, TX)
Q&A: Biogen's Multiple Sclerosis Drug Tysabri Mar 10, 2006
PML is thought to be caused by a virus called JC virus (JCV). Most people are exposed to this virus in childhood and carry it in a dormant state but never develop illness. (Food Consumer)
Tysabri Waltzes through FDA Advisory Panel by 12-0 Vote Mar 10, 2006
The JC virus, discovered in 1971 and named with the initials of the patient in whom it was found, is present in almost everyone but only destroys the brain when somethings damages the immune system and allows the virus to run rampant ... By suppressing the immune system, Tysabri allows the JC virus, ordinarily latent in a patients kidney, to travel to the brain via the bloodstream, where it begins uncontrolled replication ... According to Dr. Russell Katz, director of the FDAs Division of... (Newsinferno.com)
FDA official - If MS drug back on market, some patients could die Mar 8, 2006
Should sales resume, even more patients - perhaps one in every 1,000 - will get the often-fatal JC virus believed to cause PML, Dr. Russell Katz, director of the FDA s Division of Neurology Products, told the agency s Peripheral and Central Nervous System Drugs advisory committee. . (Boston Herald)
FDA Official Still Wary About MS Drug Mar 8, 2006
Should sales resume, even more patients -- perhaps one in every 1,000 -- will get the often-fatal JC virus believed to cause PML, Dr. Russell Katz, director of the FDA's Division of Neurology Products, told the agency's Peripheral and Central Nervous System Drugs advisory committee. "There will be additional cases of PML, and perhaps many cases, and there will likely be considerable mortality associated with use of the drug, and this is a fact that is not likely to change," Katz told the panel. (Herald Sun)
Biogen, Elan's Tysabri Is Worth Rare, Fatal Risk, Patients Say Mar 4, 2006
PML occurs when an infection called the JC virus evades the body's immune defenses and penetrates the central nervous system ... Researchers theorize that Tysabri may subdue defenses meant to keep the JC virus out of the brain. (Bloomberg)
Anti-inflammatory Drug's Potentially Deadly Side Effect Found To Be Rare Mar 4, 2006
In patients with PML, the virus (named the JC virus for the first patient it was identified in) destroys the cells that make protective sheaths surrounding brain cells ... Researchers have tried with limited success to treat MS with immune suppression drugs before, Clifford notes, without ever previously unleashing the JC virus on the brain ... "There has to be something very specific about the way the body controls the JC virus that is being affected by the action of natalizumab," he says. (Science Daily)
Analysis: Tysabri review finds no more PML cases Mar 3, 2006
One way of proceeding with the drug would be to test patients for the JC virus, which is thought to be the culprit that causes PML, Major said. Most people are exposed to the JC virus, but it generally does not cause problems unless they become immunocompromised ... Although 44 patients were referred to the committee because of possible PML, MRI irregularities or high levels of JC virus, none of them turned out to have the condition. (United Press International)
