Despite risks, many staying with Tysabri
Cases of brain disease don't deter doctors, patients
Email|Print|Single Page| Text size – + By Todd Wallack
Globe Staff / August 2, 2008
Two years ago, Matt Cavallo faced an awful dilemma: He could continue suffering with multiple sclerosis, a disease wreaking havoc with his body, causing memory lapses, a bout of blindness, and other debilitating symptoms. Or Cavallo could try a powerful new drug, Tysabri, that carried a worrisome side effect - it was linked to a rare and potentially fatal brain disease that had already killed two patients taking it, sickened another, and temporarily forced the drug off the market after just three months. The treatment's US label warns that 1 in 1,000 patients could possibly contract the disease, called progressive multifocal leukoencephalopathy, or PML, scary odds for a side effect that could prove fatal.
But the 32-year-old real estate developer said that since he started using Tysabri 18 months ago, he has felt healthy for the first time in years. And the Weymouth resident said he has no plans to stop using the drug, even after its maker, Cambridge biotech Biogen Idec Inc., reported Thursday that two more patients have come down with PML, the first cases since Tysabri was reintroduced to the market in July 2006.
"I feel like Tysabri has given me back my life," Cavallo said. "With anything you do, there is a risk-reward. In my case, it has far outweighed the risk."
Despite Thursday's news that two patients in Europe were diagnosed with PML, many doctors say they are sticking by the drug. Tysabri remains the best hope for many MS patients who have tried other drugs without success, they said. Nearly 32,000 patients are currently taking the MS treatment, including 13,900 who have been using it for at least a year. In January, the Food and Drug Administration also approved Tysabri for patients with more serious cases of Crohn's disease. And when it approved the reintroduction of Tysabri for treatment of MS two years ago, the agency concluded the benefits outweighed the risk of PML.
"This is a highly effective therapy that continues to significantly benefit the lives of patients," said Dr. R. Philip Kinkel, an associate professor of neurology at Harvard Medical School.
Indeed, some doctors and analysts even saw a silver lining to Thursday's news - the two patients who contracted PML are in stable condition, creating hope that if PML is detected early enough, doctors might be able to successfully treat it. When Tysabri was reintroduced in 2006, doctors began monitoring patients more closely for any signs of PML.
"The good news is that vigilance works," said Dr. Tim Vartanian, chief of Beth Israel Deaconess Medical Center's MS division. "The question is whether these patients will recover . . . and we don't have that information."
Nor do doctors know how many more cases of PML will crop up as patients continue to use the drug. All of the patients who have developed PML were on Tysabri for at least 14 months.
Regardless, the news clearly spooked investors. Shares in Biogen Idec plunged 28 percent yesterday, dropping it to its lowest price in more than a year. And shares in Elan Corp., the Irish company that comarkets the drug, fell even further - 51 percent. Biogen Idec relies on Tysabri for about 15 percent of its revenue, but was counting on that figure to grow. Sales have more than tripled so far this year. Now its growth potential is less certain.
MS interrupts the flow of information from the brain to the rest of the body, causing a wide range of symptoms, from numbness to paralysis. It affects more than 400,000 people in the United States.
Vartanian, who is also an associate professor at Harvard Medical School, spent hours yesterday in his office, calling patients taking Tysabri to let them know about the latest incidents of PML and to check on their condition.
"They are concerned, but they want to stay on the drug," he said.
Some feel they have no other options. Cavallo, for instance, said he found out he had MS in 2005, when he woke up and couldn't feel his legs. He was 28 and temporarily paralyzed from the waist down.
For a time, doctors treated Cavallo with interferon and other drugs. But Cavallo said he developed a serious allergy to interferon. The only other drug his doctors thought would likely work was Tysabri. But doctors also warned him of the risks.
"I was nervous about this thing called PML," Cavallo said. "But I didn't have much of a choice."
Since taking Tysabri, Cavallo said, he hasn't had any flare-ups of MS, called relapses. And Cavallo said he no longer worries about the drug's safety, despite the latest incidents of PML.
"I would be more nervous if Tysabri was not available," he said.
Todd Wallack can be reached at email@example.com.