June 20, 2008 -- A new drug called laquinimod appears to be a promising treatment option for adults with the most common form of multiple sclerosis (MS).
Phase II study results published in this week's edition of The Lancet show that laquinimod tablets safely and effectively reduce disease activity in patients with relapsing-remitting multiple sclerosis (RRMS). Current MS treatments must be given by injection.
MS is an autoimmune disease that damages the central nervous system. The body's immune (defense) system attacks myelin, the material that covers and protects nerve fibers. Nerve damage and inflammation gets worse over time, and leads to symptoms such as numbness, tingling, fatigue, loss of vision, and in severe cases, paralysis. People with the relapsing-remitting form of the disease have flare-ups followed by times of partial or complete recovery. According to the National MS Society, about 85% of people are first diagnosed with this form of MS.
The international study involved 306 adults aged 18 to 50. Patients could participate if they had one or more flare-ups in the previous year and at least one MS lesion visible on a special MRI test called a gadolinium-enhancing (GdE) scan. The study did not look at clinical disability.
Researchers randomly assigned patients to one of two doses of laquinimod (0.3 or 0.6 milligrams) or a placebo (fake pill).
The patients received brain MRI scans and clinical assessments before and several times during the study so researchers could monitor brain lesions, which would help them determine the drug's effectiveness. Scans were done every four weeks for nine months.
Giancarlo Comi of the Institute of Experimental Neurology at the University Vita-Salute in Milan, Italy, and colleagues found that, compared with placebo, patients who received the higher dose of laquinimod had more than a 40% reduction in the average number of GdE lesions over the last four scans compared with the one taken at the study's start. There were no statistically significant effects seen between patients who took the lower dose of laquinimod and the fake pill.
Treatment appeared well tolerated. Researchers reported no deaths. One patient had a pre-existing blood clotting disorder and developed a clot of a large vein that carries blood from the liver. The drug was stopped and the patient was treated with blood-thinning medication. Two patients had high levels of liver enzymes.
"Overall, the efficacy and safety profile emerging from this and from a previous phase II clinical trial, in combination with the oral route of administration, make laquinimod a promising therapeutic opportunity for patients with relapse remitting multiple sclerosis," the researchers concluded in the journal article.
A larger-scale phase III trial to examine the benefits and risks of laquinimod treatment is under way.
In an accompanying comment, Mayo Clinic researchers B. Mark Keegan and Brian G. Weinshenker said that further studies are needed to compare laquinimod "head-to-head" to existing MS treatments to see if the new drug is superior or just as effective.