An article in the August 1 edition of The Wall Street Journal reports that two patients treated with Tysabri have contracted progressive multifocal leukoencephalopathy (PML) a potentially deadly brain infection. Neither patient has died.

Tysabri was recalled in 2005 because of similar incidents, much to the dismay of many MS patients. At last, there was a new weapon and a new reason for hope in our war against MS. It has been back on the market since July 2006 and, at this time, there are no plans for a second recall.

The ongoing controversy over Tysabri, understandably, has many multiple sclerosis patients on edge. Count me in.

As with all prescription medications, the potential benefits must be weighed against the potential risks. Biogen Inc. places the risk of PML at 1 in 1,000 in the first 18 months of treatment. In clinical trials, 2 MS patients got PML; 1 patient with MS died; 1 patient with Crohn's disease died.

Studies show that use of Tysabri reduces the number and the severity of flare-ups in MS patients. Given the risk of PML, physicians generally reserve the use of Tysabri to patients whose condition is deteriorating quickly, or for those who are unresponsive, or cannot tolerate other MS medications.

Only doctors and infusion centers can prescribe or deliver the medication. It is given once per month, over several hours, through an IV. Thorough followup with medical professionals is necessary. The decision to take advantage of Tysabri requires careful consideration and doesn't come easily to doctors or their patients.

Multiple sclerosis, while a mild disability for some patients, is devastating to others, resulting in complete disability. For people who must live their lives in a body that no longer functions, potential risks take on a different level of importance. Sometimes it just comes down to the quality of life. Sometimes it is worth the risk.

I haven't had to use Tysabri yet. In my case, the possible benefits do not outweigh the risks. As with many things associated with MS, I would like to keep my options open. I want to see Tysabri remain available to people who have no alternatives and wish to take advantage of it. I hope it is there when and if I need it.

Absent overwhelming evidence of danger, with the guidance of a physician, and with full knowledge of the risks and benefits, patients should be allowed the right to decide to choose Tysabri... or not.