Bayer drug delays MS in half of patients: MRI study

CHICAGO (Reuters) - A long-term study of brain scans in multiple sclerosis patients showed only about half of the patients who took the drug interferon beta 1-b got a long-lasting benefit, U.S. researchers said on Monday.

Patients in the small, three-year study were treated with the Bayer drug, which is sold under the trade name Betaseron in the United States or Betaferon elsewhere.

The drug is designed to reduce the number of disease flareups.

Multiple sclerosis occurs when the immune system attacks the myelin sheath protecting nerve cells. It affects 2.5 million people globally and can cause symptoms ranging from vague tingling to blindness and paralysis.

The researchers were looking to see how the drug affected active brain lesions that can be viewed on magnetic resonance imaging or MRI. These lesions often show up before patients develop symptoms of the disease.

"Many clinical studies have demonstrated the ability of interferon beta to reduce contrast-enhancing lesions," Francesca Bagnato of the National Institute of Neurological Disorders and Stroke and colleagues wrote in the Archives of Neurology.

In the study, 15 people with MS had monthly exams and MRIs for six months before treatment and three years during treatment.

"The results show that on close monthly MRI inspection, approximately half of the patients fail therapy from an MRI perspective," Francesca Bagnato and colleagues wrote.

They did find that a few patients had a delayed response to the drug. Researchers noted that the study was small and the findings were not definitive.

A recent 5-year study suggested that early treatment with Betaseron was more effective when given at the first sign of the disease than if treatment is delayed.

MS drugs are often given only after the second attack because the disease is difficult to diagnose.

(Reporting by Julie Steenhuysen; Editing by Maggie Fox and Cynthia Osterman)