Gilenya: An Introduction
In September of 2010 the FDA approved the first oral medication for relapsing-remitting MS, fingolimod (Gilenya). The daily dose is 0.5mg. The medication is derived from a fungus and interacts with a receptor (called the sphingosine-1-phosphate receptor) on lymph nodes. Blocking this receptor traps certain immune cells, known as lymphocytes, in lymph nodes. This prevents them from reaching the brain and spinal cord, which causes inflammation in MS patients. This inflammatory process causes MS relapses and plays an important role in the accumulation of disability, especially early in the course of the disease. It is hoped that the medication does not interfere with the overall health of immune function in the rest of the body because the lymphocytes are still active within the lymphatic system.
The two main trials of Gilenya used to gain FDA approval were called the FREEDOMS trial and the TRANSFORMS trial. In the FREEDOMS trial, Gilenya was compared to placebo, while in the TRANFORMS study, Gilenya was directly compared to Avonex, one of the older, first-line medications in MS. Both of these studies were randomized and “double-blinded,” meaning that neither the subject of the study nor the treating doctor knew which medicine they were receiving during the trial. Subjects in the TRANSFORMS trial took a pill and gave themselves weekly injections, though only one of these medicines was real. Such studies are considered the “gold-standard” for clinical trials in medicine. The main end-point in each study was the reduction of relapses.
These were large studies, enrolling nearly 2,500 subjects between them. The FREEDOMS trial lasted for two years, while the TRANFORMS trial lasted for one year. Both of these trials enrolled patients who had MS symptoms for a relatively short amount of time, around 7-8 years, and the average age of each participant was about 36 years old. Their average score on the EDSS (the main scale used to measure disability in MS) was only 2.0, a rather low number indicating minimal disability. In these trials, two doses of Gilenya were studied, a higher dose of 1.25mg, and a lower dose of 0.5mg. Only the lower dose was approved by the FDA. Currently, a trial is underway to evaluate the safety and efficacy of Gilenya in primary progressive MS. This is due to be completed in 2013. In future posts, I will discuss the results of these studies and the role, I believe, Gilenya should play in the treatment of MS.
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