Researchers Identify MS Patients Vulnerable To Drug Related Brain Infection

An MS drug known as natalizumab, also known for its brand name Tysabri, has been linked to the development of a rare brain infection that can prove to be deadly. Now, researchers from Biogen Idec, makers of the said drug, said that it has identified which MS patients are more likely vulnerable to developing the said brain infection while taking the powerful MS drug.

Tysabri was developed as a drug that mainly delays the progression of multiple sclerosis. It has been introduced in the market since 2005. But it has since been removed due to reported medical problems that some of the patients using the said drug have encountered. Tysabri works by dampening the body’s immune system, thereby reducing inflammation, a major symptom of multiple sclerosis. But it is this effect that can also cause MS patients to be vulnerable to the JC virus. This virus can cause damage to the brain and cause a fatal condition called progressive multifocal leukoencephalopathy.

The JC virus is quite common and affects abut half of adults by the time they reach middle age. But the immune system normally is able to fight it off. But with a weak immune system it can cause and infection that causes progressive multifocal leukoencephalopathy that, when left untreated, can cause cognitive problems such as speech and balance problems, unusual behavior and even paralysis. The condition can also cause permanent disability and can be fatal.

The study involved researchers examining various statistics to find out which MS patients who took Tysabri are at high risk of progressive multifocal leukoencephalopathy. The blood samples of over 5,900 MS patients were also analyzed. The study showed that just more than 1 percent of the patients showed signs of being exposed to the JC virus had also taken immune suppressing drugs before taking Tysabri and had been taking Tysabri for 25 to 48 months. The risk for those who have not been previously exposed to the JC virus prior to taking Tysabri was 120 times smaller at 0.009 percent.

This may show that MS patients who are also taking immune suppressing drugs along with or prior to taking Tysabri are those that may be highly likely to develop progressive multifocal leukoencephalopathy, despite the low percentage found among the MS patients studied. Patients might still need to talk to their physicians about Tysabri treatments and weigh the possible benefits versus the potential risks. The study is published in the May 17 issue of the New England Journal of Medicine.

Source: Medicine Net

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