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Experimental drug slows progression of multiple sclerosis

April 17, 2012|By Thomas H. Maugh II / For the Booster Shots blog
  • In MS, nerves of the central nervous system (shown) lose their protective myelin sheaths. A new drug, ONO-4641, seems to help.
In MS, nerves of the central nervous system (shown) lose their protective… (National Multiple Sclerosis…)

An experimental drug called ONO-4641 reduced the number of lesions in patients with relapsing-remitting multiple sclerosis by as much as 92%, Colorado researchers reported Tuesday. The drug must undergo a larger clinical trial before it can be approved for general use, but the early results suggest it could be a major new addition to the slowly growing armamentarium against the cruel disease.

MS is an autoimmune disease in which the body's immune system attacks the myelin that surrounds and insulate nerves, effectively short-circuiting them and making movements difficult. An estimated 400,000 Americans now have MS -- 2.1 million worldwide -- and another 200 patients are newly diagnosed each week. For reasons that are unclear, the disease affects two to three times as many women as men, and people with a close relative who has the disease are about 20 times more likely than normal to develop it themselves. Relapsing-remitting MS is marked by periods of flareups or exacerbations in which the disease progresses, interspersed with periods of remission. About 85% of MS patients suffer relapsing-remitting MS as the first stage of their disease.

 ONO-4641, developed by Ono Pharmaceutical Co. Ltd. of Osaka, Japan, works differently than existing MS drugs. It traps destructive lymphocytes (white blood cells) in the lymph nodes, preventing them from reaching myelin and damaging it.

Dr. Timothy Vollmer and his colleagues at the University of Colorado in Denver studied 407 adults with relapsing-remitting MS, giving them one of three different diseases of the drug daily for 26 weeks. All of them had had either two relapses in the previous two years or at least one in the year prior to the onset of the study. Vollmer reported at a New Orleans meeting of the American Academy of Neurology that 92% of patients receiving the most-effective dose of the drug, 0.1 mg., had 92% fewer lesions at the end of the study as measured by an MRI.

Side effects included slower heartbeat, blood pressure changes and a block in electrical conduction between the atria and ventricles of the heart. About 1% of the patients receiving the most-effective dose developed abnormally low levels of lymphocytes in the blood.

Existing treatments for the disease include interferons, such as Avonex, which tamp down the immune system; Copaxone (glatiramer acetate) and Tysabri (natalizumab), which tamp down the immune system by different mechanisms. All are given as injections. Gilenya (fingolimod), the newest approved medication and the first oral drug for MS, reduces the number of lymphocytes in the blood.

Biogen Idec Inc. has an experimental drug called BG-12 that is being reviewed by the Food and Drug Administration.Teva Pharmaceutical Industries Ltd. has an experimental drug called laquinimod that is in phase 3 clinical trials.

Twitter: @LATMaugh

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