Nov. 6, 2002 -- Millions of people take statins to lower their cholesterol, but early studies suggests these drugs may also be useful in the treatment of multiple sclerosis and other autoimmune diseases like rheumatoid arthritis and type 1 diabetes.
In newly published research from the University of California, San Francisco and Stanford University, the cholesterol-lowering drug Lipitor prevented disease progression and reversed paralysis in mice with a multiple sclerosis-like disease. And an Austrian study, published last month, found that the statin Zocor slowed the growth of immune cells associated with progression of multiple sclerosis (MS).
While the laboratory findings offer the promise of better treatments for MS and other immune system diseases, they have yet to be confirmed in human trials. A small study involving 32 MS patients is now underway in South Carolina, and the California researchers hope to enroll around 125 patients for a trial set to begin next year.
"Statins may have [immune-system modulating] activity that could be relevant to different autoimmune diseases," researcher Scott S. Zamvil, MD, PhD, tells WebMD. "The potential application is there, but we need to do clinical trials in patients to determine if we see the same results."
MS is a progressive disease, in which the body's immune system attacks healthy tissues, causing inflammation in the brain and spinal cord. Specifically, one of the immune system's key cells -- known as the T helper cell -- prompts an inflammatory response, which over time wears down the protective coating on nerve fibers in the brain. Once damaged, the coating, or myelin sheath, is unable to transmit signals effectively from the brain to the rest of the body -- causing symptoms from difficulty swallowing to blindness and paralysis.
The first hints that statins can regulate damaging inflammatory responses came in the mid-1990s, when one of the first drugs in the class was found to reduce rejection and increase survival in heart transplant patients.
In the current study, reported in the Nov. 7 issue of the journal Nature, Zamvil and colleagues examined the effects of Lipitor in mice with a disease similar to advanced multiple sclerosis. The drug was found to lessen paralysis. And it kept paralysis from occurring in mice with MS-like flares. In mice experiencing their first attack of MS, the drug prevented progression to fully established disease. In animals that had already had a first attack, and were developing symptoms of a first relapse, treatment was found to reverse emerging paralysis. Temporary, but recurring, paralysis is a major symptom of MS.
A major objective of human trials, Zamvil says, will be to determine the optimal dosage in MS patients. In the mouse studies, the best responses were seen with the highest doses given. The California researchers plan to start human trials using 80 mg of Lipitor -- the highest dose approved by the FDA for lowering cholesterol.
The researchers plan to study patients in the earliest clinical stage of MS for one year to determine whether the statin can reduce the risk for a second recurrence. If effective, it would be the first drug for the disease that can be taken orally.
MS expert Patricia O'Looney, MD, says the animal studies are promising, but worries that some patients may demand to be put on the therapy before critical questions are answered in clinical trials. She points out that statin use is associated with a low, but troubling, risk of muscle damage. And there is little existing information on statin use among patients with MS, because patients tend to be younger than people most often put on the cholesterol-lowering drugs.
She also notes that findings from the Austrian study published last month were mixed. While statins were shown to reduce certain inflammatory responses, other inflammatory responses appeared to be turned on by the drugs. O'Looney is director of biomedical research at the National Multiple Sclerosis Society, which co-funded the California study.
"There are still a lot of questions and we won't have the answers until we do clinical studies," she says. "That is why we are trying to convey that it is important for patients to proceed with caution."