Copaxone (glatiramer acetate) is a disease-modifying therapy marketed by Teva Pharmaceuticals and approved by the U.S. Food and Drug Administration (FDA) for the treatment of relapsing-remitting multiple sclerosis (RRMS). The medicine has been shown to reduce the number of relapses in multiple sclerosis (MS) patients.
How Copaxone works
MS is a progressive neurodegenerative disorder in which the immune system mistakenly targets the myelin protein. Myelin is the main component of the protective sheath that insulates nerve fibers. This triggers inflammation and causes damage to the brain and spinal cord, leading to a wide range of symptoms.
Copaxone is a small synthetic protein, made to mimic a fragment of myelin. It consists of four amino acids, the building blocks of proteins, that are found in myelin.
The exact mechanism of how Copaxone reduces the frequency of relapses in RRMS is not known, but it is thought that the medicine modifies the immune response against myelin. For example, Copaxone may act to increase the immune system’s tolerance to myelin through repeated exposure, in a similar way to a vaccine.
Another mechanism could be that Copaxone may alter which immune cells are active; it may be able to induce a type of immune cells called suppressor T-cells that secrete anti-inflammatory proteins and prevent damage. Copaxone may also act to prevent the activation of T-cells that target and attack myelin.
While Copaxone can reduce the rate of relapses and slow the progression of MS, it cannot reverse or cure the disease.
Copaxone in clinical trials
Copaxone has been studied in several clinical trials.
The key clinical trial that led to Copaxone’s approval for marketing was a study called the Copolymer 1 Multiple Sclerosis Study, carried out in the 1990s. The randomized, double-blind, placebo-controlled Phase 3 trial enrolled 251 patients with RRMS who received either Copaxone or a placebo daily for two years.
The initial results, published in the journal Neurology, demonstrated that patients receiving Copaxone had a 29 percent reduction in their relapse rate compared to those who received placebo. Patients also were assessed in terms of their change on the expanded disability status scale, after two years of treatment compared to the start of the trial. On average, patients taking Copaxone had an improved score after two years, while the score of patients in the placebo group had worsened. The treatment was well-tolerated, with the most common side effect being a reaction at the injection site.
Following the end of the trial, patients were given the chance to continue treatment in an optional extension study. The results of this extension study showed that after one to 11 months of follow-up treatment, the benefits of Copaxone were maintained, and no long-term complications were observed.
A total of 208 patients of the original 251 opted to participate in this open-label extension study in which all of them received Copaxone. A final report of the trial and the extension, which spanned a total of about six years, was published in the journal Multiple Sclerosis. Copaxone continued to provide a sustained reduction in relapse rate and slowed worsening disability.
More recently, the effectiveness of Copaxone given at a higher dose, three times weekly instead of daily, was assessed in a randomized placebo-controlled Phase 3 trial (NCT01067521) called GALA. A total of 1,404 participants with RRMS were recruited worldwide to receive Copaxone or a placebo for one year. This also was followed by an open label extension study.
The results, published in the Annals of Neurology, confirmed that Copaxone reduced the number of relapses compared to placebo, by about 34 percent. The patients also were assessed by magnetic resonance imaging (MRI) to check for lesions, or areas of damage, in the brain. Copaxone was associated with a significant reduction in the number of lesions compared to the placebo.
Copaxone is administered as an injection under the skin. Common side effects include reactions at the injection site (such as itching, swelling, redness, pain, or bruising), anxiety, chest pain, shortness of breath, palpitations (pounding or irregular heartbeat), flushing, hives, and swollen lymph nodes.
The FDA originally approved the therapy to treat RRMS in 1996, and in March 2009 expanded this to include clinically isolated syndrome. In 2014, the FDA approved the higher-dose of Copaxone taken three times a week as a prescription, following the results of the GALA trial.
Generic versions of Copaxone also are now available.
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