An Overview of the MS Process, Terminology, and Clinical Trials
Eighty-five percent of people with multiple sclerosis (MS) begin with relapsing-remitting MS (RRMS), with temporary symptom flare-ups or "relapses." If untreated, 90 percent advance to secondary-progressive MS (SPMS) within 25 years, experiencing a progressive worsening of symptoms. The majority of individuals not initially diagnosed with RRMS are diagnosed with primary-progressive MS (PPMS), which involves a gradual but steady accumulation of neurologic problems, without relapses or remissions. A small percentage of patients have progressive-relapsing MS (PRMS), which is a progressive course from the onset with acute relapses.
MS is a neurologic disorder affecting the nerves of the central nervous system (CNS), consisting of the brain, optic nerves, and spinal cord. Nerve fibers (axons) have a protective, fatty-rich protein covering known as myelin. With MS, the body's immune system malfunctions and sends disease-fighting cells into the CNS to destroy its own myelin.
To reach the nerves within the CNS, the immune system cells and molecules must cross a protective barrier that lines the brain's blood vessels, the blood-brain barrier (BBB). The immune system's white blood cells include lymphocytes. These may be B cells, which produce antibodies to fight against "foreign invaders" (such as bacteria or viruses), or T cells, which help to regulate the immune response. Another type of white blood cell is the macrophage, which ingests and destroys foreign substances.
The attack creates inflammation along the nerves where the myelin and axons are experiencing damage. These areas of disease activity are lesions. With the help of oligodendrocytes (cells that produce and maintain myelin), damaged myelin may be restored through remyelination, particularly early in the disease. Lesions may be viewed by a magnetic resonance imaging (MRI) scan of the brain and/or spine. Inflammation can be better evaluated with gadolinium enhancement - a type of dye given to the patient via injection.
The Kurtzke Expanded Disability Status Scale (EDSS) gives scores from one to 10 to measure disability, largely in terms of mobility. Other assessment scales for MS include Kurtzke's Functional System (FS) and the MS Functional Composite (MSFC).
Clinical trials ensure the safety and efficacy (effectiveness) of potential treatments. Studies conducted in the United States need to be reviewed and approved by the Food and Drug Administration (FDA).
Phase I trials test for safety in humans. They are usually small, and typically involve fewer than 100 "healthy" volunteers. Investigators usually observe how the human body responds to the medication, determining safe doses and related side effects.
Phase II trials typically run up to two years. About 100 to 300 people with the disorder (in this case, MS) are given either the active drug or a placebo to determine a drug's safety and efficacy.
Phase III trials can take several years to complete and involve 1,000 to 3,000 participants at different medical locations. These trials evaluate safety and efficacy, as well as additional benefits and adverse reactions. If the results are favorable, an application for approval is submitted to the FDA.
Phase IV trials are conducted after a drug has been approved. Participants are enrolled to further monitor safety and side effects, while evaluating long-term efficacy.
For more information, please refer to the "Health and Wellness" column of the Summer 2007 issue of The Motivator. MSAA also offers a monograph titled, Understanding Clinical Trials. To view, download, or order free copies online, please visit MSAA's website at www.mymsaa.org. To order free copies by phone or to speak with a Helpline consultant, please call MSAA at (800) 532-7667.Back
|Last Updated on Tuesday, 29 January 2013 16:55|